Client warning "The following files or folders are still open"

Those documents seem to be open in Windows Explorer - or at least that's what Windows thinks.  Has she accessed them at all during the session?

I assume this just happens for one user, so something unique to her desktop?  Maybe anti-virus or similar?

It is just one user. It is PDF documents that she has created from a template in M-Files, or that she has downloaded from her browser. It is not all files that she has worked on during the day, but just a few. I am not sure what, in her desktop, is still seeing the file as open. So strange.

I will check with my IT Security person on anti-virus software.

It may be worth raising this with support. I could throw some guesses around but they may be able to better structure the investigation.