The instruction here in this forum don't have the "?c".
Without it, nsis leaves one temp folder for each execution.
System::Call 'user32::OpenClipboard(i 0)'
System::Call 'user32::EmptyClipboard()?c'
System::Call 'user32::CloseClipboard()?c'
Empty Clipboard-Full $pluginsdir
2 posts
`?c` means the cdecl calling convention is used. Windows API is normally stdcall, including these specific API functions. Your change creates stack corruption and probably masks another problem. Post a complete example that reproduces the temporary folder that's left over and I'll have a look at it.