Office 365: Mail attachments from Outlook cannot be opened in Word/Excel (Nov. 2023)

[German]A quick question for administrators in the readership who use Microsoft Office 365. A reader has contacted us because problems are occurring in his environment when opening mail attachments from Outlook. The attachments cannot be opened in Word or Excel. Updating the Intel® Arc™ & Iris® Xe graphics driver for Windows could help.


Blog reader Uwe posted a direct message on Facebook last week because he had encountered a problem with Microsoft Office 365 at his customers. The environment states that the clients are running the Windows 11 operating system (I postulate the current version 22H2 or 22H3). Microsoft Office 365 is also installed on these machines.

Attachments cannot be opened

Uwe wrote that he had received reports from three different customers about a problem with Microsoft Outlook and mail attachments. The error pattern is quite simple:

  • Emails that arrive with a Word or Excel document attached are correctly displayed as an attachment in Microsoft Outlook.
  • However, these files from the attachment cannot be opened by Word or Excel.
  • The associated Office application opens, but the actual file with content is not displayed.

The strange thing is that other files and Excel documents that are stored on a server, on the desktop, on Dropbox or a similar storage location can be opened by the user in Word or Excel as normal and without an error message.

Customers then tried to save the attachment from Outlook to the desktop. But that is not a solution, wrote Uwe. Even if the customer saves the attachment from the email to the desktop, for example, this file is still not usable.

Office documents seem to be broken

Uwe has come to the conclusion that the document files in question from the mail attachment on the Windows 11 client in question are simply defective. The following observation is quite curious:


  • If the user tries to open the email with the corresponding attachment from Outlook Web Access (OWA) and then access the Word or Excel attachment, the same behavior as outlined above occurs. The file cannot be opened.
  • If the user now forwards this defective file to colleagues or stores the attachment on the server, colleagues can open this document with the relevant Office application and view the content.

Uwe concludes that any Microsoft Office document file that is sent to the affected user by e-mail is defective. If the user receives an e-mail with a PDF attachment, this attachment or the document works perfectly.

What was tested

Uwe writes that the Office quick repair and also the complete repair of the Office version have already been carried out, but without success. Microsoft Office 365 has already been completely uninstalled and reinstalled in the 32-bit version. Unfortunately, this did not help.

Office 365 was then removed again in the 32-bit version and reinstalled in the 64-bit version. However, all attempts were unsuccessful and did not work.

The assumption that an ESET virus scanner used by the customer was corrupting the files was also not confirmed. According to the reader, the ESET virus scanner was removed without any improvement.

According to the reader, the error with the corrupt document attachments even occurs when the customer has integrated his private email address in Outlook and retrieves it. Uwe therefore concludes that it necessarily has something to do with Microsoft Office 365, but suspects that the error is in Outlook.

Old post from June 2023

Uwe noted in his message that I had already written something about this in June, but that no one had contacted me since then. It must be the blog post Outlook 365 damages PDF and Office files since April 2023. It addressed the problem of attachments suddenly breaking in Outlook since April 2023.

In the blog post, I had linked to the Microsoft Answers forum post Outlook 365 keeps corrupting PDF and Office files from May 10, 2023, where the problem was confirmed by other users. The thread in question is five pages long, but no solution appears.

Uwe told me, that he hasn't been able to find anything in forums on the Internet either. He has emailed the error description to Microsoft support. However, I have not yet received any feedback from Uwe that there are any new findings. So I would like to ask whether other users or administrators of Microsoft Office 365 have also observed this behavior of Microsoft Outlook?

Further reader messages

After publishing the German post, I saw that Patrizia left this comment and asked whether there is a solution to the problem. She writes that the problem is spreading in her environment, despite the updates she has carried out. According to her, it doesn't just affect Outlook. Documents from SharePoint Online are now also causing the same problem.

As a temporary solution, Patrizia was only able to define the following workaround in her environment: OWA does not always work. Resending the email to your own mailbox does not cause the error. However, the error occurs if the document is opened directly or downloaded and then opened. In SharePoint, the error can be avoided by first opening the document in the browser and then opening or downloading it in the app.

German blog reader Lars G. contacted me by email on November 15, 2023 (I just came across it again while cleaning up my inbox). Lars wrote:

We have been experiencing Office problems for a week now. Office files randomly stop opening.
A message appears in Word, Excel etc. when opening…

Fehler beim Öffnen von Office-Dateien

This error hits all Office versions that we use [i.e.] 2019/2021 and O365. This is also independent of where you open the files from. Desktop, folder, network drive

One workaround we have used so far is to set the storage location as a trusted storage location in Office. Then it works again to open the files. However, this cannot be the solution.

We suspect a connection with the Windows 11 23H2 update, as only Windows 11 clients are affected and this fits in with our timing.

The reader pointed out that there are already similar entries in forums such as German Although the post does not address Outlook and its attachments, it does address Office problems in connection with Windows 11, and this is where the following piece of the puzzle falls into place: the Intel Arc & Iris graphics driver could be the cause.

Intel Arc & Iris graphics driver as the cause?

Note this German comment from Sebastian with the advice to update the Intel® Arc™ & Iris® Xe Graphics – Windows driver to version The driver was released on November 13, 2023 and should fix the problem according to the comments. It is currently unclear to me why a graphics driver has this effect – in any case, I have not found any reference to the problem in the release notes (PDF).

Similar articles:
Outlook 365 damages PDF and Office files since April 2023
Outlook bug for slow saving fixed – fix being tested with insiders

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