Sometimes when SSDT / Visual Studio freezes during execution you get the message below because if you kill SSDT, the SSIS debug host will still be active by locking the ISPAC file.

The solution : You’ve probably already restarted SSDT, but that didn’t help. Open Task Manager (Ctrl + Shift + Esc) and locate DtsDebugHost.exe under Process and finish this process (maybe several times, finish them all). Now try running the package again.