Unable to preview any MS Office documents in Outlook 365 after Windows 10 repair

Question

My Windows 10 networking stack died recently, requiring a rescue repair-install from a USB key. Everything is now working fine except I am no longer able to preview Office documents in Outlook 365. The error for Word is:

This file cannot be previewed because of an error with the following previewer: Microsoft Word previewer

Same issue with Excel and PowerPoint. PDF previews still work fine (using Acrobat).

I've tried both a quick and a full online repair of Office 365. I've tried toggling settings in the Trust Center as described here https://www.technipages.com/outlook-fix-this-file-cannot-be-previewed .

Any suggestions for how to get Outlook preview to start working again for Office attachments?

Windows 10 Version 21H2 (OS Build 19044.1288)
Office 365 Version 2204 (Build 15128.20178 Click-to-Run)

Answer 1

Hi @Adam Kessel ,

Glad to hear this issue has been resolved!
Thanks for the sharing.

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However, due to a recent update in forum policy, the question author now is not able to accept their own answers.

So I have written a brief summary of the solution this issue. Please feel free to accept it as the answer, which would benefit others who also has similar issues in forum.

Solution:
Go to HKLM\System\CurrentControlSet\Services\BFE in regedit and add 'local service', 'network service' and 'nt service\bfe' all to the security list with at least modify permissions and set those permissions to be recursive for all the keys under BFE.

Answer 2

Found a solution. I had to go to HKLM\System\CurrentControlSet\Services\BFE in regedit and add 'local service', 'network service' and 'nt service\bfe' all to the security list with at least modify permissions and set those permissions to be recursive for all the keys under BFE. Now Windows Defender finally works again, as do Outlook document previews.

Answer 3

The troubleshooting tip, for future reference, is that Outlook preview of Office documents won't work if Windows Defender isn't running. This isn't obvious from any of the error messages. Then, on top of that, the fix to get Windows Defender running in my situation was tricky -- somehow after doing a system restore, the permissions for relevant keys in the registry were incorrect.

Answer 4

This solution works for my problem!