Attempting to run
rbxtsc in PowerShell results in an error like this:
This happens if PowerShell is not configured to run scripts downloaded from the internet (like roblox-ts).
You can allow this by running the following command in PowerShell as an administrator:
Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser
You can run PowerShell as an administrator by right-clicking the Windows logo in the bottom left corner and selecting "Windows PowerShell (Admin)"