When a command doesn't work as expected you should follow these steps to ensure that it is a true bug and not a human error:

If none of the above solves your issue then here's the recommended way to proceed:

AntiVirus Issues

It was occasionally reported by a few users that some AntiVirus can interfere while scripts are copying or deleting files. It's advisable to temporarily disable the anti-virus only when debugging the building process to check for possible causes that keep your project from being concluded as expected.

Under normal circumstances there is no need to disable your Antivirus. But, please be aware that antivirus programs will scan any files being copied which may impede performance.