This may apply to other PS extensions, but PSM1 files is what I was working with. When I unblocked them, I was able to apply the change without any errors. However, when I returned to the properties of the files, they were still blocked. My account is a member of the administrators group that has full-control of the files.
There are two problems here:
1. There was no error even though unblocking the files did not work.
2. The files did not get unblocked.
I was able to get around this problem by giving my account explicit permissions to the folder where the files resided.