MS office files open as read-only

I have noticed that when I double click on MS Office files, they often open as read-only as if the file is open elsewhere. This may be related, but when I try to delete some items they cannot be deleted (for the first few tries) because the file is "in use by Directory Opus". Is there an option I need to check, or could this be related to the files being in a OneDrive folder? Thanks.

If the viewer pane is open, try closing it.

Also check if the same happens with the same files if you open them from File Explorer instead of Opus.

Antivirus / anti-ransomware / privacy / etc. tools could also affect how documents are opened when launched by different software.

Thanks Leo. I think you are right and it is the viewing pane. That would explain why it is an intermittent issue. Should have thought of that.

You can make the viewer open a copy of the files, but it shouldn’t normally be needed if the Office viewers are working correctly, unless you’ve turned on the Legacy mode for very old versions of Office.

Thanks Leo. How do you make it open a copy. I couldn’t find the option in preferences. Thanks.

Configure the ActiveX plugin under Preferences / Viewer / Plugins.