Attached Link: Process monitor

As the title to this thread says, this is very weird. If the problem returns and you are curious to find out if the file is being deleted by Daz Studio (seems unlikley) then the sysinternals Process monitor will show detailed file operations for a process. It's not the easiest tool and consumes a lot of your time but is useful in these cases.

This seems too specific to be a disk corruption problem but might be a good idea to catch up on any backups you do just incase.