Drag and Drop problem, XP guest Win10 host

[Namdoog]

New to VirtualBox, running XP SP3 on a Win10 machine. Have been dragging and dropping files between guest/host with no problem for a couple of days, then ran into this error with a particular file:

Drag and drop operation from guest to host failed.

Current drop operation still in progress.

Result Code: E_FAIL (0x80004005)
Component: GuestDnDSourceWrap
Interface: IGuestDnDSource {dedfb5d9-4c1b-edf7-fdf3-c1be6827dc28}
Callee: IDnDSource {d23a9ca3-42da-c94b-8aec-21968e08355d}

My VB version is:

VirtualBox Graphical User Interface
Version 5.1.26 r117224 (Qt5.6.2)

Rebooting virtual and physical machines didn't fix it, then I discovered the problem is just with a couple of files, so I can still drag and drop others. I think the big clue is that the two affected files were involved in a local copy operation using drag-and-drop within the VM earlier. For now I will try avoiding that sequence!

Anyone else experienced this sort of problem?

[mpack]

It's a common problem, usually happening when a permission problem blocks the copy: the other end of the process is left dangling.