ERROR code: 0x80070185

We are having the same issue here is our findings.  No resolution.

• We have the problem on libraries with less than 100 documents in it as well as larger ones so no correlation to the 5000 list view threshold.
• It only effects office documents, pdf files and other files like images open fine.
• Clicking Try Again or Skip seems to then allow you to open the file.
• Once the file has been opened the issue seems to go away for that particular file, even if right clicking and telling to to Free up Space.
• Users with this problem also report other issues with syncing that may be related to this issue. They will open certain files and it will say that it cannot upload because the path is invalid, when this occurs you can see files in the office upload center in an error state.
• I have validated that it is not an issue with https proxy traffic decryption by removing my PC from our proxy tunnel and going direct to the internet and still had the issue.
• Reboots, unlink account, uninstall / reinstall, none of these will fix the issue.  It seems somewhere deep in the OS something is hung with particular libraries for users.
• I cannot narrow it down to any particular library, some users have a problem with one library that other users have no issues with.  I can't seem to find a way to always replicate it.  I just know that once the machine seems to have a problem with a library it always has a problem with that library.
• I ruled out AV software by disabling it on my machine, still had the issue.
• I disabled bit-locker thinking it might be related to drive encryption, we had issues using Dell DDP with onedrive when we initially rolled out windows 10 and moved to BitLocker but that had no effect.
• I sync the drive from a different PC using my same credentials and the new PC doesnt have the issue.

This definitely seems to be PC related with the sync and not anything to do with the particular SP library or User Account.

Ok thanks, have you managed to test if sync/push helped one computer or all? I know all computers in my case wont have enough harddisk space for full library sync.

Our users have the same bad habit, constantly reusing Office 97-2003 format documents as templates.

While these files present the same error, along with other issues and errors, we have seen this particular 0x80070185 error on files that are in the newer Office formats as well.

Since doing the offline sync/push to cloud process I described above, I have not been able to reproduce the error on my machine, files open fine.

Could this be related which version of Word or Excel was used to create file? I've seen this in one tenant where we migrated files from file share and there are 10-15 year old documents and it seems to happen specifically on old .doc documents which are large containing lots of pictures. 

Users have usually bad habit of using old documents as templates when creating new ones.

We are having the same issue. One of the libraries only has 600 items in it, so the issue is not due to the 5000 view threshold. We do have a couple of libraries that are over the threshold and exhibiting the same error, but the one with only 600 items has the error as well.

The one common thing between these four libraries is that the files they contain were all migrated from a local fileshare. Some were migrated via the OneDrive sync tool itself, while others were migrated with the SharePoint Migration tool that Microsoft provides. Maybe there is something about migrated files that causes the issue, maybe they are missing some hidden internal property until after you open it for the first time.

With that in mind, the error does seem to only occur the first time you try to open a cloud file. Subsequent openings of the file don't seem to produce the error, even if you push the file back to online-only (Free Up Space) then open it again, the error doesn't seem to appear. It's like you need to create a local cache of the item (or create that hidden internal property in SharePoint for the item) for it to open properly.

I am testing a process of making an entire synced library available offline (Always keep on this device), then pushing everything back to the cloud (Free Up Space). After this has been done, I am hoping that all items are 'cached' locally and open as expected without error. It seems to work so far.