First off, this is only happening to me on an external mapped NAS.
I am running the latest version of DOpus (v12.7 x64) on Windows 7 x64 and currently up-yo-date with Microsoft Updates.
I have 4-Drive QNap NAS mapped through the standard "Map Network Drive" function in DOpus in the format of "\192.168.1.xx\Public\Vol_1", "\192.168.1.xx\Public\Vol_2" etc. This has been happening for as long as I can remember (at least a year or so) although I don't recall if it happened with v10 or v11.
Anyhow over the years I have grown accustomed to pressing Shift-Del whenever I want something to be permanently deleted. However when pressing Shift-Del on a folder stored on the NAS drive, the folder disappears as you would expect it to but if you then say hit F5 to refresh the view, the folder reappears. The folder is empty of files but the folder itself still exists. The only way to get rid of the folder is to highlight the folder and hit Del (NOT Shift-Del).
I realize I don't need to hit "Shift-Del" when deleting from a networked drive but it is habit. The issue therefore isn't really a problem for me as it is easily remedied by pressing Del. Which is probably why I haven't reported this sooner.
If you could make a Process Monitor log of what happens, we could take a look at that.
I suspect this is a bug on the QNAP side though. There have been a few and they don't always implement the filesystem correctly. (e.g. If they report success when trying to delete a folder that is not empty, we'll assume it succeeded and won't look for contents to delete, since they told us it succeeded. But they would be wrong to do that.)
Updating the QNAP firmware and software is also recommended as issues like this are often fixed by them once reported.
To make a Process Monitor log:
Download Microsoft's Process Monitor and extract the zip somewhere. (No installation is required.)
Double-click Procmon.exe to launch it and accept the default filters.
Make sure it is logging filesystem events. It should be by default, by just in case, make sure the icon is activated, so the toolbar looks like this:
With Process Monitor still logging, perform the action in Opus, then wait about 10 seconds.
Back in Process Monitor, use File > Save, select the Native Process Monitor Format (PML), and save the log to somewhere.
Zip up the log. It will be quite large if not compressed, but much smaller when added to a zip file.
Send the result to crashdumps@gpsoft.com.au or via a private message. Don't post the log publicly, just in case it contains anything you don't want the world to see.
Of course now that I have opened a ticket about it I have been unable to reproduce it. I should have originally stated that it happens about 40-50% of the time. I will send the dump asap.
As I suspected, this looks like a problem on the QNAP side.
The log shows that Opus asks to delete the folder, and is told it succeeded.
(Process Monitor logs folder deletion as a combination of CreateFile(Access:Delete) and SetDispositionInformationFile(Delete:True), which are the low-level filesystem APIs that Windows APIs like RemoveDirectory call internally.)
If the folder is still there afterwards then either something re-created it immediately (which the log doesn't show happening from the machine doing the logging, at least) or the NAS did not really delete the folder.
Possibly of interest is the svchost.exe process trying to access the folder just after it is deleted and getting a CSC OBJECT PATH NOT FOUND error, which suggests the folder really isn't there right after deletion, but is perhaps still being returned in folder listings? (e.g. The NAS or Offline Folders may be caching things and not updating their cache properly.) Or it may mean something is going wrong between the Offline Folders feature in Windows and the NAS. (The CSC errors seem to relate to Offline Folders.)
As an aside, a lot of operations performed against the NAS take a very long time to process, which seems unusual if it is on a LAN, unless the disk or network are under heavy load. That may not be relevant to the problem but may also suggest something is up with the NAS or the harddrive inside it.
icon is activated, so the toolbar looks like this:
