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Decode FAQ

Here are answers to "Frequently Asked Questions" ('FAQ') on decoding Internet Email attachments. This document is oriented towards Decode Shell Extension. However, the information is also of interest to Explorer Extensions or Directory Toolkit  users.

If you have a question that is not answered here, write


Decode Shell Extension
Compatible with Windows XP 32-bit and Above
Decode Shell Extension Screenshot


>>Virus Information - Protect Yourself<<

Program Information

  About Decode Shell Extension

  Do You Have A 64-bit Version For Windows 8?

Installation Issues

  Installing Decode Shell Extension

  setupdx.exe - I downloaded it but can't find it

  Readme.txt appears when starting computer 

  How Did Your Program Get on My Computer? 

  No Decode My Right Click Menu

  No Decode In My Start Menu

  No Decode In My Email Program

  Is there a secret fee for use?

  Is Decode Shell Extension Spyware or Malware?

  Will Funduc Software Decode Attachments For Me?

Decoding Steps

  Basic Decoding Steps

  "File Not Encoded" Response

  Decoded Files Named NONAME

  Decoding Multiple Mails (Concatenate)

  Can't Decode WebTV Messages

  Mail Problems & Suggestions

  How Can Correspondents Send 'Plain Text' Messages To Me?

  POP3 Problems & Suggestions

Opening Files

  "Open With" Message

  Cannot Open the Files Sent to Me

  I Clicked on MIM - Nothing Happened

  Cannot Find America.exe

Other Information

  What Encoding Types are Supported?

  Creating Encoded Files

  Tell me more about encoding &decoding

Virus Warning - If you are sent a program as an email attachment that you can run, or a document that can execute a macro, your computer can become infected with a virus. Purchase an up-to-date anti-virus software and use it!! Keep your virus definition files current!!


General Program Information

Decode Shell Extension is a freeware internet email attachment decoder for decoding files that contain one or more internet email attachments. The program works from Windows Explorer only. 

Basic usage is that you first save the complete internet message - text and attachment - to a file on disk. Then use Windows Explorer to navigate to the file you saved, highlight the file, right click, and select 'Decode' from the menu. See Basic Decoding Steps for more information and follow the above links to the examples for more information on actual usage.

Decode Shell Extension can decode Base64(MIME), yEnc, BinHex (Mac format), quoted-printable, plain text, XXENCODED, yEnc, and User (table) encoded files. The program can decode multiple attachments within a single message files and multi-part files (already concatenated).

Please note: The term "decode" for our program does not refer to tasks such as unlocking password encrypted zips or password protected documents or anything having to do with audio or video 'decoder' software. Our program is for internet email attachments only.

Do You Have A 64-bit Version?

No! And there are no plans to create a 64-bit version. If your computer is a 64-bit operating system you will need our Explorer Extensions utility or Directory Toolkit. Explorer Extensions (shareware) is similar to Decode Shell Extension in that it works from Windows Explorer. Directory Toolkit is a standalone file manager and directory synchronization utiility with decode & encode functions. Both Explorer Extensions and Directory Toolkit come in native 64-bit versions.

Do not make the mistake of thinking you can somehow trick Decode Shell Extension into working on a 64-bit computer! Your efforts will fail. Tactics such as 'compatibility mode', 'Windows XP Mode', or tinkering  with file permissions will not work and you may cause further problems for your computer if you start fiddling with your system. Decode Shell Extension is a 32-bit 'dll'. Windows Explorer 64-bit simply will not load a 32-bit 'dll'.


Q: How do I install Decode Shell Extension?

I. Review these instructions

Because you will need to exit the software you are using now to read this, review these instructions in their entirety now. Perhaps print this page. Or save it to your hard disk - From your web browser's File Menu, select Save As. At minimum, write down some notes. 

IMPORTANT NOTE FOR ALL USERS: Do not experiment with your installation and try to trick Decode Shell Extension into doing something it was not designed to do. The dll only works with Windows Explorer. There is no way to coax it into decoding files automatically or getting a decode function into your AOL or Incredimail menus.

- DO NOT save setupdx.exe to your Startup folder!!

- DO NOT put decext.dll into your StartUp folder.

- DO NOT experiment with changing a Windows file association to associate a particularfile type with setupdx.exe or decext.dll!!  The program does not work that way. 

- DO NOT associate any files with decext.dll.

- DO NOT use REGSVR32.EXE to register the dll.

II. Download the installer - setupdx.exe

Download the installer, setupdx.exe, via links we provide on our www site by visiting the program home page at The file size is approximately 650K.

You must keep track of where your www browser saves the installer. We have no control over this so it is up to you to know where it gets saved on your hard disk. Consult the help documentation for your www browser if you do not know where downloaded files are saved. 

III. Exit All Software

Before you run setupdx.exe to install you should close all running programs such as word processors, web software, email programs, etc. It is good practice to do this before running any installation program. 

IV. Run setupdx.exe to install Decode Shell Extension

There are two ways to do this, both of which involve knowing the location where setupdx.exe was saved in step III above.

Method A

1. Click on Start, Run

2. Click on the "Browse" button and navigate your way to where setupdx.exe was saved in step III. Highlight setupdx.exe once you get there and click on "Open".

3. Follow the installer's instructions from there. We recommend you let the installer use c:\tools\decext for the destination path.

4. Restart your computer.

Method B

1. Click on "My Computer" to open a Windows Explorer view of your hard drive. "My Computer" will probably be the icon in the top upper left of your Windows desktop.

2. Navigate to the folder where setupdx.exe was saved on your hard disk. Depending on your windows settings you may only see 'setupdx' and not the complete file name, 'setupdx.exe'.

3. Double click on setupdx.exe.

4. Follow the installer's instructions from there. We recommend you let the installer use c:\tools\decext for the destination path.

5. Restart your computer.


Q: I downloaded setupdx.exe but when I typed Start Menu - Run, setupdx.exe the computer responded "... Cannot find setupdx.exe or one of its components...". Where is setupdx.exe?

A: We cannot help you directly with this. You will need to investigate where your web browser saves downloaded files.

If you cannot locate setupdx.exe, perhaps try using the Windows Find Files or Folders utility (Start Menu, Find). If you still cannot locate it, download it again, this time making note of where it is being saved to on your computer.


Q: How did your program get on my computer? I don't want it there.

A: A human who had access to your computer installed it. None of our programs install themselves by magic. A human physically needs to take at least two steps: Download the installer and then run the installer. Funduc Software has never created any programs that installs themselves. Furthermore, you can't 'pick up' any of our programs simply by visiting our www site. Our site simply doesn't work that way. Nor do we work with any other companies that include Decode Shell Extension with an installer for another product.


Q: Is there is a hidden charge each time I use Decode Shell Extension?

A: NO! The program was previously released as "contribution-ware" whereby it was free but we asked for a $5.00 contribution for email support and automatic email notification of program updates. As of 2013 the program remains free in current form. Email support is no longer available.



Q: Is Decode Shell Extension some kind of spyware?

A: ABOLUTELY NOT!!! The program does nothing to communicate any information about your computer or online activities to us.  


Q: I downloaded setupdx.exe but nothing happened. I don't see a Decode option in my Windows Explorer right click menu.

A: Did you run setupdx.exe to install the program? See the Installation Instructions.


Q: Where is the Decode Shell Extension program item in my Windows Start Menu?

A: There isn't one. All functions are via a Folder/File view from Windows Explorer. Highlight a file in Windows Explorer and right click with your mouse. "Decode" will activate Decode Shell Extension on the highlighted file. "Decode" is not present when a folder is highlighted.


Q. How come I can't find the Decode menu in my Email program.

A. There won't be one. Decode Shell Extension works from Windows Explorer only.


Q: Your annoying "Readme.txt" about Decode Shell Extension comes up every time I re-start my computer. Make it stop!

A: This is not by design! Promise! We would never intentionally harass users like that. We have never seen this ourselves but please try the suggestions below.

Uninstall and Reinstall

Possibly something went amok during installation. 

1. Uninstall Decode Shell Extension via Start -> Settings -> Control Panel -> Add/Remove Programs. Look for Decode Shell Extension in the list of programs. Click on the Add/Remove button.

2. Reboot your computer.

3. Run setupdx.exe again but this time carefully review the Installation Instructions first.

Remove "Decode Shell Extension Info" from your Windows Startup Folder 

For reasons unknown, the shortcut to the Decode Shell Extension readme.txt file may have ended up in your Windows Startup folder. Anything in that folder is run (or displayed) automatically when you start your computer. To check for and remove the shortcut to the readme.txt:

1. Open up a Windows Explorer view of your hard drive. This can be done by clicking on the "My Computer" icon on the top left of your windows desktop.

2. Navigate to C:\WINDOWS\Start Menu\Programs\StartUp.

3. Look for a shortcut named "Decode Shell Extension Info"

4. Delete "Decode Shell Extension Info" to the Windows Recycle bin or, if you want, move it to C:\Windows\Start Menu\Programs\Tools. C:\Windows\Start Menu\Programs\Tools is where "Decode Shell Extension Info" belongs.

Remove setupdx.exe from your Windows Startup Folder 

Did you somehow manage to get the actual install program into your Windows Startup folder? Users have sometimes done this. The result is that the program re-installs each time you start your computer.

1. Open up a Windows Explorer view of your hard drive as above.

2. Navigate to your way through the folders on drive C: until you reach C:\WINDOWS\Start Menu\Programs\StartUp.

3. Look for an actual file named "setupdx.exe" or a shortcut that points to setupdx.exe. The latter will might be named something like "Shortcut to setupdx.exe" or "setupdx.exe". The size of the file will be small. The icon will probably have a little arrow in it.

4. Move setupdx.exe to another folder where you keep your install programs &/or delete the shortcut to setupdx.exe.


Q. How do I use Decode Shell Extension to decode a message?

A. Follow these steps:

1. Use your Email software and save the entire message as a text file. For most Email programs you will find a "save" function under the File/Save menu. Make note of the filename and path you use when saving the message to a file.

2. Use Windows Explorer and navigate to the file you created in step 1.

3. Highlight that file, Right-click with your mouse, and pick Decode from the right-click context menu.

4. The program will automatically detect the attachment format and provide you with prompts for file names and overwrites.

5. See the American Online or CompuServe examples for step-by-step pictures.


Q. How can I decode the file to another directory?

A. When prompted, click the "Change Name button" and select a different directory.


Q. I can't decode my attachments. What is your general advice?

A. Attachments sometimes simply refuse to decode properly. This may not be the fault of your email service. Here are some general tips.

- Tell your correspondent set their email program to send messages to you as "plain text"!!! Tell them that to NOT use "html" or "rich text" messages. This is very very important!!! The majority of attachment problems involve "html" format messages. We made enhancements to our decoding software to handle this but the highest probability for success will be if your correspondent uses "plain text" formatting for their messages. If your correspondent uses Outlook Express or Outlook, they can change the default settings for your address to 'plain text' in the address book or possibly the Tools-Options-Send tab.

- Tell your correspondent to send ONLY ONE attachment per message!!!

- If you are dealing with images, have your correspondents send only .gif or .jpg format images (one per message).

- A tactic for multiple images is to have your correspondents send you a single word processing document with the images embedded in the document. This method that you and your correspondent have compatible word processing programs.


Q. I received a mail message that has the attachment spread out across multiple messages. I decoded the first message but the attachment is truncated. If I decode the second the program tells me the file is not encoded. What can I do.

A: Decode Shell Extension can handle multipart attachments if they are in a single file. Therefore you must combine the multiple messages into a single file. 

The process of combining multiple individual files into one single file is called 'concatenating'. 

Our shareware utilities Directory Toolkit and Explorer Extensions have a built-in concatenate function that can be used to combine separate individual files into a single 'target' file. You can even change the order by which the separate files are added to the single large file. This is important because for the single large file to decode properly, you need to add the separate files in the correct order as per what the person who sent you the messages intended (usually the sender's mailer handles this OK).

Let's say you have the saved messages - message1.txt, message2.txt, message3.txt. To decode those you need to get them into one single file and then decode that resulting single file. bigmessage.txt seems as good a name as any for the single file (the file name doesn't matter) so what you would do is concatenate message1.txt, message2.txt, message3.txt to the target file, bigmessage.txt. You must do them in that order! If you use the order, message1.txt - message3.txt - message2.txt -> bigmessage.txt, bigmessage.txt won't decode properly. Directory Toolkit & Explorer Extensions let you control the order visually.

If you are technically minded you can also concatenate files manually from the MSDOS command line. Please see the command line help for the 'COPY' command. To do this, go to a MSDOS prompt and type 'copy /?'. 

An example manual concatenate of the above would be: 
  copy message1.txt + message2.txt + message3.txt bigmessage.txt

Please do not write us for support with MSDOS commands or using the MSDOS shell. If you are baffled by such things and much prefer a nice Windows program, get Directory Toolkit or Explorer Extensions.

Note for Outlook Express Users: If you receive a large mail attachment that Outlook or Outlook Express divides into multiple files when saving to disk, the order of the files may not make much sense. The file names &/or section numbers may offer little guidance about what order you should use when concatenating the individual files to a target file. A general convention is that the smallest file is the last section. If you decode and end up with an invalid file you can try experimenting with the order in which the files are concatenated. Or, if you want to avoid getting into guessing randomly, write your correspondent and ask them for advice. Perhaps they can deliver the file using another method. 


Q. How can correspondents send 'Plain Text' messages to me?

A. We cannot provide support for other email programs so it really is up to your correspondent to study the program help for their email program for instructions on how to do this. If you want to give your correspondents a 'head start', tell them to look in a 'Format' menu of some kind when they are composing a message. Look for a 'Plain Text' choice. That is the one to use. Do not use 'HTML' or 'Rich Text'.


Q: I right clicked on a file and Decode Shell Extension tells me the file is not encoded. What gives?

A: First, is it possible that the saved message does not contain a message attachment? If the original message contained only one attachment, perhaps your email software decoded the file already and that is what was saved on your hard disk. Double click on the file and see what happens. If you can open the file, you are all set. If you get a "Click the program you want to use..." type message, then perhaps the file is not encoded but you don't have the correct program installed. See Cannot Open the Files Sent to Me.

If Windows give you a "Click the program to use... MIM file" or "Cannot open MIM" type of message, the problem may be an error in the raw message that leads Decode Shell Extension to conclude the message is not encoded. Forwarded messages are a primary culprit when this happens. If you are the third or fourth 'forwardee', by the time you get the message it is such a mess that Decode Shell Extension cannot make sense of what's there. 

Another cause is an outright error in the message. This is probably what happens with forwarded mail - somewhere along the line a sender made a user error or their email program made a mistake.

The solution is to write your correspondent, tell them you could not receive their message properly, and ask them to send again. Tell them that if they are forwarding something they should save the attachment(s) first on their end, create a fresh message to you, and then add the attachment(s) they received. If there were multiple attachments in the original message, tell your correspondent to send you one fresh message per attachment. If the message is not forwarded, make sure your correspondent sends only one attachment per message. For example, if someone has several pictures to send you, have them send the pictures on at a time - one picture per message. Also make sure your correspondent is using a 'Plain Text' message format when they send their attachment.


Q: I right clicked and Decode Shell Extension tells me a file was successfully decoded. But when I double click on the MIM file I get an "Open with" message telling me to click the program to use to open the MIM file.

A: Don't double click on the original raw message. You have to locate and click on the file(s) that were created when Decode Shell Extension decoded the original raw message. By default Decode Shell Extension creates these in the same folder as the original message. Press F5 to refresh Windows Explorer and update the file list. The file(s) should be there.


Q: The attachment decoded OK but when I answered "Yes" to Decode Shell Extension's "Would you like to open it?" prompt it gave me a funny message about "Open with... Click the program to use..". Why won't Decode Shell Extension open the file?

A: Write your correspondent back and ask them what program you need to have installed on your computer in order to open what it is they sent to you. 

Decode Shell Extension only decodes the email message. To actually open/view/work with that attachment file you also have a program installed on your computer that can handle that file. The Decode Shell Extension "Would you like to open it?" prompt relies on the Windows "file associations" for your computer. The "Would you like to open it?" prompt does the same thing as if you double clicked on the saved attachment from Windows Explorer. If you get a funny "Open with... Click the program to use.." response that means your computer is not set up to handle the file that was sent to you.

For example, if you receive a Quattro Pro spreadsheet, you won't be able to deal with that file if you don't have a software installed on your computer that can open a Quattro Pro spreadsheet.

It is possible that, in fact, you have something installed but your Windows installation does not automatically recognize the particular file that was sent to you. Take this up with your correspondent.


Q: When I click on a file I get a message telling me "Cannot find America.exe".

A: Technically, what happened is that a program was installed on your computer that modified the "file association" for the file type you are trying to deal with.  "America.exe", whatever that is, is now apparently gone from your computer but the disturbance to the file associations remains. 

The exact source and purpose of "America.exe" is unclear. For the record -- It is definitely not a Funduc Software program.

There is no single solution that we are aware of for the 'America.exe' issue.

One solution has helped some users is to re-install your zip utility. Our Directory Toolkit is a zip/archive manager. This corrects the file associations with zip archives and gets "amercia.exe" out of the picture.

Another solution is to write your correspondent and ask him/her what program you need to deal with what they sent to you. It is possible you already have the necessary program installed.

If you clicked on a .gif or .jpg file and got the "Cannot find America.exe" message, try opening the file with your web browser. All modern web browsers can view these image files.

Also see your Windows operating system help for additional instructions and background information concerning "file types", "file associations", and "file extensions".


Q. My email program can't decode a multiple attachment message I received. I have a standard POP3 mail account. Can you help?

A. Is the message coming to you in "html" or "rich text" format? Our own experiments indicate that "html text" or "rich text" format messages sent by one email program may not be understood properly when received by another email program. For example, Microsoft's Outlook Express does a fine job handling multi-attachment html text messages sent by someone using Outlook Express. But the receiver may have trouble if they're using another brand of email program. Our decoding software may or may not be of help here. We suggest that you are having ongoing problem with a particular sender, ask them to use "plain text" messages. If that doesn't help, try having them send only one attached file per message.


Q. I can't decode a message from my friend who has WebTV.

A: Decode Shell Extension may or may not work. Review the other information in this FAQ and/or take it up w/ the WebTV folks.


Q. Can you fix & decode my attachment for me if I send it to you?

A. Do not send us your problem attachment!!! We cannot provide ongoing support for a freeware product. For ongoing support you need to purchase Explorer Extensions or Directory Toolkit. As a registered user, if you have ongoing problems with a particular sender we would help you fix the initial problem rather than continually debug problem attachments.


Q. Why is the decoded file named NONAME.DAT and how do I open it?

A. If the program that encoded it did not specify the original file name, Decode will still decode it but will use that default name. When decoding, you can click the Change Name button and use the correct name and extension. If you're not sure what name and extension to use, write the person who sent it to you and ask them.


Q. The decoded file is corrupt. Why? I pasted the message text into Word, then saved it to a file and tried to decode it.

A. Word and other editors may add extraneous characters to the file and corrupt the attachment. Instead, use the File/Save menu from your Email program to save the message to a text file.


Q: I received some Word documents and I think they decoded OK but when I try to open the files I set a "WINWORD cannot locate file" type of message.

A: Are you using the Decode Shell Extension 'open file' function? If so, do not let Decode Shell Extension launch Word (e.g., click on 'no' when Decode Shell Extension asks 'Would you like to open it'). Instead, open Word separately, use the Word File Open menu to navigate to the file, and open it from within Word. As we have seen with other softwares, under some conditions, some versions of Word have problems with automatic launching and opening of files.


Q. What types of encoding are supported?

A. Decode Shell Extension supports Base64(MIME), yEnc, BinHex (Mac format), quoted-printable, plain text, XXENCODED, and User (table) encoded files. Support for yEnc is new to version 4.6.


Q. How can I encode a file and send it to someone else?

A. Decode Shell Extension only decodes files. You'll need either Directory Toolkit or Explorer Extensions if you want to create an encoded file.


Q: Please tell me more about encoding & decoding.

A: Encoding refers to a general process in which files are "translated" into a form containing only pure text / ASCII printable characters. Encoding schemes were developed to allow binary files such as graphic images, programs, or ZIP archives to be sent across computer networks that support only pure text messages. Internet Email & Usenet newsgroup messages, for example, only permit pure text to be sent.

Encoded files are sent as "attachments". In most cases, they are '"attached" to a message that includes some conversational text plus the encoded file(s).

Sending a binary file via Email is a two step process - the message sender first sends an encoded attachment and person receiving the message then decodes the attachment back into original form. Many email programs handle the encoding/decoding process automatically. Other mailers, such as the email component of the AOL software, require the message receiver to decode the mail using an external program when the message consists of more than one attachment. 

For more reading, try a search from your favorite internet search engine for 'RFC 821' and/or see the links below. Note that some of the links below very old so results may vary:


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