Mail.app corrupting attachments

You've stated 10.8.3 twice, did u mean 10.8.4?

Mine are not being moved, but are still corrupting. Something is happening within Mail as I restarted Mail and left the Mac for a whole day. When I went to use Mail and attach a document, it corrupted it. So something is happening over time and in the background to cause this problem.

Hi Gary, yes, sorry, I meant both 10.8.3 and 10.8.4. No, restarting app or OS does not change anything, files are currupted forever (but I can get them again from Gmail webmail).

Let's hope this bug gets fixed in 10.8.5 or in Mavericks.

This bug is driving me crazy and affecting my work.

I had this problem on my MacBook Air - 10.8 -> 10.8.5. Yesterday I got a MacBook Pro Retina, brand new install of everything. And it still happens. I had just thought it was my MacBook.

Absolutely shocking. There must be a setting in Gmail that Mail.app doesn't like.

I limit my IMAP folders to 1000 messages - that's the only setting I've changed. Anyone else do this? Perhaps that's the common theme.

Sure this won't help many, but I discovered why mine was corrupting attachments. Basically I had another problem which was attachements that were naturally embedded in Apple Mail outgoing emails, couldn't be accessed by windows users.

So I had to change it so that they were actually attached/appended to the end of the mail, rather than embedded.

It seems that there is no standard setting to allow that, so after some forum searches I found some code that I could put into the Apple Terminal utility application that would do it. Basically some short code that was either set as TRUE or FALSE, which turned embedding off.

That did work... but I've since discovered after turning that code off again, that none of my attachments are being corrupted any more. So that was definitely the cause for me.

Hope that may help others who've done the same thing.

defaults write com.apple.mail DisableInlineAttachmentViewing -bool yes

This helped me. Rebuild mailboxes after that.

Thank you for the script AndreyKovel This has fixed a long running problem for our business.

Awesome! Thanks. I had exactly the same issue, and was going crazy with it.

I have an IMAP account, and on both my iPad and my newly set up Android phone the messages looked good, but a few were corrupted on iMAC. Up until now. Glad to have bumped into this thread. Thanks again!

This issue is related to 64-bit message encoding and how attachments are processed. Apple has no permanent fix for this issue. Sigh!

Instead of rebuilding an entire mailbox, which involves re-downloading all the messages in that mailbox, you can fix corrupted messages this way ...

1. Create a folder in IMAP called temp

2. Search for the locally corrupted messages by typing "base64" in Mail's search box

3. Drag-and-drop the corrupted messages into the temp folder

4. Make sure the temp folder is selected then click Mailbox > Rebuild

5. When the messages have been rebuilt, quit Mail

6. Reopen Mail and drag-and-drop the messages back to their original folders.

If you don't quit Mail in step 5, the messages will not be repaired. You can check your repair by searching for "base64" again.

Ahhh, I've been having a similar problem for a while now. .pdf attachements open and are readable on screen, but print as blanks OR a pop up says the file is corrupted. Then I recalled having the same problem in the distant past, and Apple Support told me to "rebuild" the inbox.

So I just went to the inbox, then at the bottom of the "Mailboxes" drop-down menu clicked Rebuild. Then I went back to the message with the troublesome attachment and it printed normally.

Apparently, mailboxes occasionally get corrupted by something dropped into them, and rebuilding (which only takes a second or two if you don't have heaps of old mail in your inbox) returns them to working order.

No, simply rebuilding the inbox does not solve the attachment corruption issue. Attachments that are contained in mailbox folders and have "aged" are randomly corrupt. This problem has not been fixed by Apple for over 2 years now, making it impossible for me to use Apple Mail. Really a sad situation. I was told by several Apple specialists that this is known by Apple and they have not fixed it and that they recommend to not use Apple Mail if accessing historical attachments is critical.

Roger

Dears,

I had the same problem of corrupt attachments (mainly when they are larger) with Apple Mail in combination with GMAIL.

This solved my problem:

In GMAL (Settings/Labels) I have disabled the LABELs "All Mail" and "Important" to be available in IMAP (unmark "Show in IMAP"). This solved the "corrupted attachments" issue and also some issues of sometimes mails not appearing in the folders where I moved them to but only in the "All Mail" folder...

Maybe the bug of the corrupted attachments is related to Apple Mail trying to download the same attachment simultaneously for two (or more) different folders... (can someone in Apple verify this, please ?).

Regards,

A very similar issue has just occurred for me, only for certain email messages sent with attachments using Mail.app.

The issues is as follows:

- Send email from Mail.app that contains a digital signature and a PDF attachment.

- Do not add text to the body of the email, only the attachment.

- It does not seem to matter if the email message contains a signature.

Once the email message has been sent, viewing the message in the Sent mail folder (in this case it is a Google Apps IMAP folder) and you receive a warning that Mail.app cannot verify/read the digital signature and the message cannot be decoded.

I've tried the same steps as above, except that I then added body text and the email can be read normally.

Here's another interesting piece of info: The messages that cannot be decoded by the instance of Mail.app that sent the email CAN be read successfully on my other Mac with the same version of Mail.app installed, as well as on my iOS devices.

There seems to be something about sending digitally-signed email with no body text and a PDF attachment that scrambles the message only locally using Mail.app.

And, this is still happening running El Capitan 10.11.4, but worse: Even with text in the body of the email, and even with other attachments.

Been looking for a fix on this too. My Mail app seems to corrupt files I attach and send (or even forward). Not noticed any difference whether message has text or not... fixed it for a bit after re-install of OSX but started doing it again.... argh!