All the time I have the problem that I cannot delete - move - rename folders in Windows 7 (also applies to windows 10) on network drives because of the thumbs.db file. It complains: "The action can't be completed because the file is open in Windows Explorer." I found something in a long thread that works for me.
windows 7: In explorer: Change file display settings from "details" to "Content"
windows 10: In explorer: View->Layout->List
Now the thumbs.db file can be removed.
I accidentally came across a slightly easier fix for this bug. Instead of setting "Turn off the display of thumbnails and only display icons on network folders" to Enable, I simply changed the Windows Explorer display setting from "Details" to "Content". Then I was able to delete my Thumbs.db files without any complaints from Windows 7, even though I have thumbnails enabled. After deleting the offending file(s), I just restore the display to "Details" again.
thanks my unknown hero robster8192