The first time I tried to send archived files to/from a Gmail email account was one month ago and I noticed that you cannot send these kinds of files. I tried multiple times and failed always.

If I send an email to a Gmail account, I get a reply with the text message:

This is an automatically generated Delivery Status Notification.

Delivery to the following recipients failed.


Viewing the email source, I found out this:

Final-Recipient: rfc822;anemailaddress@gmail.com Action: failed  
Status: 5.5.0 Diagnostic-Code: smtp;552-5.7.0 This message was blocked  
because its content presents a potential 552-5.7.0 security issue.  
Please visit 552-5.7.0  
http://support.google.com/mail/bin/answer.py?answer=6590 to review our  
552 5.7.0 message content and attachment content guidelines.  
m3si23238476wjw.33 - gsmtp

The archived files I tried were .zip, .rar, no password, with password, encrypted. None of them worked. The archive contained a Kicad project.

Is there a way to circumvent this?

  • So, just to be clear, what file types were in the compressed archive file? Google is pretty clear that they won't accept messages that contain archive file if the archive file has other blocked attachments in them. – Mike B Apr 25 '15 at 6:38
  • I already pointed it out: The archive contained a Kicad project. – machineaddict Apr 27 '15 at 6:05
  • Right... but for those (like myself) who are unfamiliar with Kicad, that doesn't help much. I found this page which suggests that KiCad sometimes includes .000 files which are used as temporary files. Do you have one of those files in the zip? If so, I wonder if Google is thinking it's a part of a multi-volume archive file (since programs like 7-zip sometimes split archive files up and use the file extension .000). If so, that would conflict with Google's other rule: "zip file within another zip file". – Mike B Apr 27 '15 at 6:59
  • @Mike B: no, it doesn't contain another archive or an archive extension. – machineaddict May 28 '15 at 9:28

You should try with 7zip, which use "7z" file format. The mail server in my school blocked .exe and .vbs files when they were zipped but not when they were 7zipped. So in the case of some files are not allowed by Gmail to be send or receive, it might pass the checking. http://www.7-zip.org/

  • 1
    I just sent an exe password protected file with .7z extension and it worked. It works with or without encrypting the filenames. Thanks for the idea! – machineaddict May 28 '15 at 9:49
  • This method no longer works! – machineaddict Nov 17 '17 at 10:07

Anyway, Gmail only allows to upload files until you fill up their 25MB quota per mail. Therefore, if your project grows bigger, you can use Google Drive to attach files as big as 10GB as they mention:


Other solution is for example WeTransfer where you can upload up to 2GB, it's a backup just in case Google increases their restrictions/protections for sending those kind of files.

  • Services like wetransfer delete the files to fast, have limited filesize, limit the download speed, etc and after I'm uploading the files to those services I'm not in control over what they'll with those files (not necessarily intentional, might have security issues, etc). Better narrow it down, wouldn't you agree? – machineaddict May 28 '15 at 10:07
  • @machineaddict It's hard to get control over files that someone else stores (you can only rely in their promises of being secure-with Google's great power comes great responsibility, and lots of exploiters/crackers ;P). In wetransfer, as you mentioned, they delete those files after 7 days, in gmail, they stay in both accounts. If you're really not that worried that your project may worth millions in the right/wrong hands, then Google Drive attachments seem the best solution for you atm ;) – Armfoot May 28 '15 at 10:19

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