File locked after copy

Very often,when moving one or multiple files to another drive, the origine file can't be deleted with the error "the process can't access the file because the file is locked by another process". In fact, it seems the DO try to delete the file before releasing it; solution is just to close D.O. and restart it ...
Generaly, copying files, just one is locked, others are deleted ok; the locked file may be anywhere in the copied list (first, last, middle)
If I copy the files then manually delete them, it may happen too (maybe less often).
But the problem is very frequent !
bug ? Any solution ? any debuging option ?
Thank you for help/ideas

It's probably something involved in generating the file's thumbnail, icon or other metadata. It may not be Opus itself, but something like a bad video codec which leaves files locked (if it happens with video files, for example).

Which type(s) of files does it happen with?

What's displayed of those files in the lister, columns, viewer, thumbnails, etc.?

Is it happening on local drives or on a NAS or something else?

It happens most often on video files, but that have never been looked at.
The displayed columns in the lister for this directory are just name, size, modified time, type and attributes, no thumbnail.
The copy is done from internal hard drive to usb hard drive.
If I retry the copy on the file, the error is similar, but with the precision "locked by directory opus".

You may have a shell extension installed which opens and inspects video files just to get their icons. Or something else which opens them for another reason.

Those will usually open them within the Opus process, so it would look like Opus has opened them when it had not. (It's also possible Opus itself has opened them, of course, but if that was normal we would have hundreds of similar reports, so it's less likely, unless a particular combination of file contents and settings are triggering an obscure bug.)

Generating a Process Monitor log can often reveal exactly what is leaving the file locked:

In this case, it would be best to reboot, then start generating the log before anything has displayed the folder the files are in, then perform the actions that lead to the problem and error message, and then save the log.

What is displaying that message? Opus or something else? Opus would not normally say it was locking the file itself. You would also not normally see a message like that when copying, only moving or deleting. Are you doing the copy with Opus or another tool?