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TS3276: OS X Mail: Troubleshooting sending and receiving email messages

Learn about OS X Mail: Troubleshooting sending and receiving email messages

TS3276 Corrupt Attachment in Apple Mail (using IMAP)(on Mountain Lion too)

3710 Views 23 Replies Latest reply: Jun 19, 2013 2:02 AM by Fred Tsai RSS
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Fred Tsai Calculating status...
Currently Being Moderated
Jul 26, 2012 10:24 PM

I got corrupt attachments by using Apple Mail, IMAP on both Gmail and my company email. The problem continues since Lion, Mountain Lion is the same still. Any suggestion?


This is really a trouble to me...


Look, the main reason I bought Mountain Lion on 25th this month is Mail improvement. And seems the hug problem is not solved at all... what a pity...

I might have to go back to the less integrated 3rd party apps... Can some one answer me?

MacBook Pro (15-inch Mid 2010), OS X Mountain Lion
  • Austin Kinsella1 Level 6 Level 6 (11,505 points)

    Are you saying that 70% of attachments you are getting on Mail are corrupt? Is it size related?

  • MrHoffman Level 6 Level 6 (11,720 points)

    The message sizes question has already been asked, so here are some other questions...


    Are any particular file types involved in the corruptions, or are all file types involved?


    What is the sending system?  (Are all the corrupt files from the same sending system, or are the problems here arriving from a variety of different ones?)


    What software is involved in viewing the files?    I see some Adobe software involved.  Is anything else used to view these messages, and reporting corruptions?


    Have you tried viewing the failed PDF files with Preview, for instance?  (Control-Click on the icon for the attached file and select Preview from the list of files for the Open With... option in the popup.)


    Have you tried saving the attached files from mail to your desktop, and opening the files from there using the Adobe tools and with Preview?


    Are there any anti-virus tools active either on the mail server, or on your OS X system?  If so, does disabling those change the behavior with the mail attachments?


    Is your version of the Adobe software current?  (Same for whatever other software is in use here.)


    View the raw message source, and see if the sorts of MIME file types for the attachments makes sense for the files.  If you're not sure, post the file types used for the attachments, and we'll check that. > View > Message > Raw Source


    Here's the MIME header for a multi-part message section containing a PDF:


    Content-Type: application/octet-stream;


    Content-Transfer-Encoding: base64

    Content-Description: document.pdf

    Content-Disposition: attachment;


  • Austin Kinsella1 Level 6 Level 6 (11,505 points)

    Have you any Mail plugins or add-ons?


    Are you saying that, if you access this same message with Thunderbird or Sparrow you can successfully read the attachments?

  • MrHoffman Level 6 Level 6 (11,720 points)

    It's probably best if you ring up Apple Support here, if you have that access.


    In terms of the environment, AV has a habit of getting itself entwined all over.  AV can be quite unpredictable, if (when?) it goes wrong.  (And when I'm debugging, I generally don't trust the environment; not until the pieces have been verified.)


    Try a different login with the same mail server credentials; see if it's a corruption within the local environment.


    And yes, disable plugins as Austin Kinsella1 suggests, and look for and remove any lingering input managers that might be around.  (If you're in a different login, this will happen automatically.)


    Are all the messages that are getting stomped on arriving with UTF-8 encoded filenames?  Try using the ASCII subset for the filenames.


    And do you get the same errors with a different mail server?  (Have you tried attachments from a different mail server, and determined if those too are corrupted?)

  • Austin Kinsella1 Level 6 Level 6 (11,505 points)

    Fred, it helps those trying to help you if you carefully answer any questions they ask. Remember, they cannot peep over your shoulder to see what is happening. So, you put up a screen shot of a failure to open a PDF attachment. The question I asked is, can you successfully download this message from your IMAP server using Sparrow or Thunderbird?

    If you can, then it is likely that we don't have to worry about faulty routers, internet settings or anything like that and can focus on Mail and its environment.


    As a further test, if Sparrow or Thunderbird can successfully read the same message, maybe you would create a new user account, set up Mail there and see what happens when you try downloading that message.

  • Austin Kinsella1 Level 6 Level 6 (11,505 points)

    Hi again Fred. I'm not sure why you're apologising, or who to. Just for your information, none of the responders on ASC are Apple employees or developers, just ordinary users trying to help other users.


    We have established (please correct anywhere I am wrong):


    You are using Mountain Lion.

    Attachments you receive with Apple Mail have a high chance of being corrupted.

    You have no plugins or additions for Mail.

    The corruption occurs regardless of file type of the attachment, and is not size related.

    The same attachments, when downloaded with Sparrow or Thunderbird, are not corrupted.

    The corruption also occurs with Mail in a newly-created account account.

    The corruption was occurring with Lion, but not Snow Leopard.


    I think the next thing is to see if we can find any errors relating to the downloads. Quit Mail, then find in Applications/Utilities and run it. Restart Mail, and try to access one of the failing attachments. See are any relevant error messages posted in console.

  • Austin Kinsella1 Level 6 Level 6 (11,505 points)

    Hmm. That doesn't help me. Next time you get  a message with a corrupted attachment, note the time then see if Mail reported anything in Console at that time.

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