While installing Sitecore 9.1 Initial Release (that post is available here) I mentioned that I encountered this error while installing with SIF. I just recently reinstalled Windows 10 on the machine I was using to complete the install and hadn't edited the execution policy in Powershell.

More information about execution policies is available here.

The solution is to change the Execution Policy to RemoteSigned in Powershell. There are associated risks with setting this policy so ensure to read up on it before doing it.

Additionally you can start a Powershell session with RemoteSigned so that setting won't persist to new sessions that are created later, you can do this by opening Powershell like this: powershell.exe -ExecutionPolicy RemoteSigned.