The problem you’re seeing is almost certainly windows file blocking - because the files were downloaded from the internet, they’re blocked by default.
Quick fix: Fire up a PowerShell window with Administrative rights and run the following
Get-ChildItem C:\Windows\system32\WindowsPowerShell\v1.0\Modules\OctopusDSCMaster -recurse | Unblock-File -verbose
That should unblock all the scripts under that folder and the issue should resolve. I’ve dropped a
-verbose onto the end there so you can review exactly what files get unblocked during the process
There are a number of posts on places like Stack Overflow that recommend moving the module folder as a fix - that’s not essential, but I might move it up one level from where it is now,
just because that’s a more predictable path. Having said that, it looks like it’s resolving the module fine as it is, so that step is very much optional.