[Supplement 23.11.2020]
This is a post to a blog post from 11/16/20. Please read here first
Documentation
The Microsoft documentation on Group Policy „Exclude certain file types from uploading“ is partly incorrect and incomplete.
Incorrect:
The registry key is incorrect
Missing information:
currently no Office formats are supported. I have only tested this with docx, xlsx and pptx. Microsoft has informed me that the documentation will be adapted.
In the wildcard description only the asterisk [*] is described. But also the question mark [?] works.
Examples:
| In the group policy are stored: | Files | Synchronization |
| Try.* | Tryt | Blocked |
| Try.mdb | Blocked | |
| Try.docx | Synchronized | |
| Try.xlsx | Synchronized | |
| *Exclude*.txt | A Exclude Textfile.txt | Blocked |
| A Exclude Textfile.mdb | Synchronized | |
| A Exclude Textfile.docx | Synchronized | |
| TestEx??*.txt | TestEx12.txt | Blocked |
| TestEx13.txt | Blocked | |
| TestEx4.txt | Blocked | |
| TextEx56 Try.pptx | Synchronized |
Where does this Group Policy work?
This is a computer group policy. Currently, this Group Policy applies to all synchronized areas:
- OneDrive Personal
- OneDrive for Business
- SharePoint document libraries
- Local synchronization of files „shared with me”
- Synchronization of „Add to OneDrive“ files
Existing files will still be synchronized. Only new files are scanned.
Workaround:
The user can switch to the browser and upload the file manually. Afterwards, this file will also be synchronized. So it is clear that this Group Policy cannot be used as a security feature!
Exclusion:
an exclusion on folder level is not possible.
View
The user does not (yet) get a display which names and wildcards have been created. He has no possibility to read out these parameters.
Hans Brender's Blog 
Hello,
I’m stuck trying to get it to work with Intune and Onedrive KFM.
Already to reboot or restart Onedrive and try with new *.Ink but it doesn’t work.
Do you have an idea?
Thanks
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first check without Intune.
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Just to follow up. This is now working as expected in version 21.002.0104.0004.
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Not working with 20.201.1005.0009 for me either. But I was thinking because it was OneDrive Personal and not business, though this article seems to indicate should work with personal
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It will work also with OneDrive Personal. But maybe you have to wait until 20.219.1029.0007 (from 7.1.2021) Production Ring
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Excluded *.lnk and dragged a shortcut to desktop. Still syncs.
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So you have KFM activated (PC Backup)?
After doing insert of the link, did you restart OneDrive or Rebbot your device
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This is not working in Production build 20.201.1005.0009. Any word from Microsoft as to why?
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So Microsoft say<s: it is running in 20.201.1005.0009
https://support.microsoft.com/en-us/office/onedrive-release-notes-845dcf18-f921-435e-bf28-4e24b95e5fc0?ui=en-US&rs=en-US&ad=US
And I have no issues with it.
Remember:
1) No Office files can be exluded.
2) Excluding only new files, no existing!
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What would you do with existing .pst files?
Move them to a thumb drive and then back again to the PC so that the GPO works?
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No. Import it into Exchange
Export it to Exchange Online
PST Files without inserted in Outlook may synced to OneDrive
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