There are complaints that sometimes even though the .exe / tar or other files are archived, GMail and/or other mail services scan through the archives and raise an alert prompt and don’t let you send the attachment.
Here’s another simple solution, that should solve this issue if you happen to face:
1> Place the .exe or files of any other format in a folder,
2> Compress that folder with Winrar (if you do not have Winrar, you can download it for free from here),
3> Choose password protection when you are compression,
4> Choose the option “Encrypt file names”.
This will solve your problem. Since the file names are encrypted and folders are password protected, there is no way GMail scanners or as a matter of fact any other mail scanner, look through the content and figure what’s in there. So all your attachments go through to the recipients.
Most of you may already know this, but there are a few who still are looking for this solution.