This browser is no longer supported.
Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(128, 8%, 22%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EA%3C/text%3E%3C/svg%3E)
Since April we started a new EA agreement with Microsoft and added all of our users to E5 licenses of M365 on top of the E3 licenses they already had - we were told that the E3 licenses would disappear anyway.
We don't know if that is related, however since mid-April we started to have numerous users who find their email attachments to get corrupt in Outlook. Whether it's with Outlook 2016 or 365, and Windows 10 or 11 Pro, the symptoms are always the same: the size of the attachments decrease significantly and they cannot be opened in their usual application (Adobe PDF Viewer, Word, Excel, PowerPoint, etc.).
Attachments in emails are oftentimes received already corrupt and are therefore unusable, sometimes they are good to be viewed or opened, then later on get corrupt. Sometimes
the attachments get corrupt when their related emails get forwarded to other users (who also find corrupt attachments in the emails they received).
We noticed that Outlook sometimes get even in a state where no file can get attached to a new email, or no attachment from a received email can get saved on any drive.
Whenever a user tries to open a corrupt attachment, an error message similar to this appear: "there was an error opening this document. The file is damaged and could not be repaired". No useful details get logged in the Event Viewer, all we see at the time of the error is "An unexpected error has occurred".
We tried the SaRa diagnosis program on some users' workstations with no luck, the SaRa program gets to vanish before the issue is seen again.
We tried to run Desktop Outlook in Safe Mode, the issue has not been seen. We tried to disable all of our add-ins one by one in normal mode, the issue was seen with every add-in being disabled....
We have hundreds of users and are out of ideas. Can you please help.
Using Classic Outlook on Windows for personal email, calendar, and contact management
Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.
Our Office 365 version is 2303.
We solved the issue here by deploying the following Known Issue Rollback (KIR) to over a thousand of workstations:
Windows 11, version 21H2: KB5023774 230222_032017 Known Issue Rollback
Windows 10, versions 21H2/22H2: KB5023773 230222_032013 Known Issue Rollback
Our case looks different: We are all on O365 and our desktop Outlook only is failing sometimes, randomly, to keep the integrity of file attachments in received or sent emails - no matter who are the senders/recipients. The problem has been seen with all Office document types also, not only PDF. And we don't have the problem if we only use the web version of Outlook. I hope this answers your question.
Samuel,
Up to today I have not seen any other recent cause for corrupted PDF attachments. It is most likely the CopyFile API issue which will get fixed by Windows in the Windows Updates next week ~6/13/23.
Note in the description of this issue, Windows 10, version 22H2 | Microsoft Learn. "You might have intermittent issues saving, or copying, or attaching files using 32-bit apps which are large address aware and using the CopyFile API." This issue will not happen with Office 64-bit. If in the process of those files being sent could it come from 32-bit Office or other application? If so you could test with 64-bit and see if it mitigates it.
User receives a PDF and can view it. Go to forward it on or view it again later and the file size has shrunk considerably and is no longer openable.
I have the same issue. Is there a solution? Or when is the next windows issue with patch.
Hi All,
We have installed the latest KB KB5027215 onw a windows 10 22h2 multi session vdi however we still appear to be experiencing the same issue, has anyone else tested the latest update ?