Open attachments blocked by Outlook

For some years, Microsoft has (rightly) patched security holes in Windows and its various applications. One of the things that ‘broke’ several years ago as a result of these patches was the ability to send certain attachments such as Help files (CHMs) and executables (EXEs).

For the everyday user, this is ‘a good thing’. But for those of us who work in the software industry, it’s been nothing but a darned nuisance. It makes it difficult to send legitimate working files between workers in a company, telecommuting workers, contractors, and clients.

If this is a problem for you, there are a few ways you can overcome the problem:

• ZIP the file, though be aware that some versions of Outlook can look inside a ZIP file and still stop it getting through.
• Rename the file extension to something else. For example, if you have to send xyz.chm then rename it to xyz.txt or similar, and let the recipient know that they have to rename it back to xyz.chm when they save it locally.
• Set up Outlook to allow these files through. See http://www.slipstick.com/outlook/esecup/getexe.asp for the method to do this. It requires that you hack the registry.
• Send the file to a webmail account (like Gmail) that doesn’t require Outlook, then save the attachments from there.
• Use the file transfer facilities in instant messaging-type applications, such as Windows Messenger and Skype. The other advantage with these is that the file size is not restricted as it may be with your ISP’s email settings.
• For very large file, use a file ‘drop box’ service such as YouSendIt.

I’m bound to have missed something else equally simple, so feel free to add to this list in the Comments section.

[Links last checked December 2007]