Operation is blocked by software restriction policies
On loading my profile on a new machine, as a mortal account, I would suffer this problem:
File cannot be loaded because its operation is blocked by software restriction policies, such as those created by using Group Policy
When running as admin I did not get the same issue.
When running as a mortal account:
Get-ExecutionPolicy -List
...showed me that the execution policy was RemoteSigned
Right clicking on the file in explorer, and viewing properties, I expected to see an "Unblock" button -- but there was no such button.
The trick was... it was a 0 byte file! It had been created but never populated. So I deleted the file, and all was good.