I recently stepped over this issue when trying to use git mv to move directories within a project. On my Windows 10 machine git exited with the error message “directory permission error”.
After some research I found some suggestions on Stackoverflow to kill the Explorer process. Since this is not a solution for me I played a bit around and found out that this error occures the first time when you try to use git mv and you have uncommited changes. The trick that did it for me simply was to commit my changes (didn’t push them) and after that execute the command. Worked like charm.