[d--b]

oh and the parent folder is on a shared NAS with some caching.

[gwbas1c]

We had to add logic to block network and USB drives. (They were an ever-present source of customer issues.)

The root cause of the problem is that in .net, there is a bug with File.Exists. If there is a filesystem / network error, instead of getting an exception, the error is swallowed and the call just returns false. I'm not sure if newer versions of .net fix it or not; I only learned about this when we were implementing a driver / filesystem.

[inemesitaffia]

You can just mount network drives as folders

[gwbas1c]

Which we detected and blocked, due to phantom deletions. (I explain the .net bug higher in this thread.)

[UltraSane]

You should also be able to detect if via RW latency.

[d--b]

doesn’t surprise me, network drive is the typical example of something that doesn’t “just work”.