1. Open the folder C:\Program Files\PokerStars\backup
(Depending on your PokerStars site, this folder may vary, for example, for PokerStars.EU it could be C:\Program Files\PokerStars.eu\backup
The PokerStars folder may also be in the “Program Files (x86)” directory if applicable.)
2. Copy and replace all of the contents of this folder to C:\Program Files\PokerStars
3. Run PokerStars.exe from this folder. This will run the previous version of PokerStars while disabling the updater.