I have problem moving large rar files (1.6GB) to another folder in the same drive when the rar plugin is enabled in options.
What I did was to copy the rar file, and then paste it in another folder which has the same rar filename (but older version). When I allowed the prompt to overwrite the file, I got this error.
If I disabled the rar plugin, this doesn't happen.
Is there a way to fix this?
Windows 10 Home v1903
Assuming nothing is working on the archive in parallel, my guess is this is caused by your antivirus scanning the destination archive and holding it open while Opus is trying to replace it. If so, clicking Retry should work once the virus checker releases the file.
The scan may be triggered by the Replace File dialog in Opus generating a thumbnail of the archive based on its contents (causing the archive to be opened, which may then cause it to be virus-scanned).
Good virus checkers only scan files once until they are changed (or there is a virus definitions update), but some of them scan files every time they are opened. Microsoft's antivirus is particularly bad (in almost every aspect, these days, sadly).
If you don't have any control over the antivirus, you could try preventing the thumbnail from being generated on the Opus side. (Preferences / File Display Modes / Thumbnails, Adjust folder thumbnail settings, then turn off Generate folder thumbnails from images inside folders.)
Another thing which can passively cause archives to be opened is the folder tree, if it is open. Try turning off Zip files and other archives under Preferences / Folder Tree / Contents.
It's also possible it is not antivirus but that there is something about the particular archive (and maybe others made by the same thing) which is causing things to get stuck. But antivirus would be my bet here.
After trying everything you wrote in your post, the error is still happening. However, the symptom disappears if I temporarily disable the Avast Antivirus.
I'm not sure if it's a good idea, but I've disabled "Explorer Scan" for compression files (zip, rar, etc.) and it is now working as intended. Thank you so much for your assistance.
Might be worth raising as an issue with Avast.