Can't play Deluxe Edition

[EnigManic]

I bought the Deluxe Edition on sale and played for over fifty hours.
Now when I try to play it tells me to buy the full game.

I already read about others having the same issue and I tried all the suggested troubleshooting tips to no avail.

[EnigManic]

Update: I got it working.

If this happens to you, follow these simple steps:
Make sure the game executable is NOT set to 'open as administrator'.
Uninstall the game.
Re-install the game.
Very the integrity of the game files.
Launch from Steam. (not from the game shortcut on your desktop.)