Return to Revisions

Open Terminal and enter
sudo nano /System/Library/CoreServices/SystemVersion.plist
and enter your admin password.

Change the two strings 10.10.2 to 10.9.2. Hit ctrlO and Enter to write the file to disk.

Hit ctrlX to quit nano

Leave open the Terminal window.

Install TrueCrypt 7.1a

after the installation is finished change to Terminal and enter
sudo nano /System/Library/CoreServices/SystemVersion.plist again

Change the two strings 10.9.2 back to 10.10.2. Hit ctrlO and Enter to write the file to disk.

Hit ctrlX to quit nano

enter cat /System/Library/CoreServices/SystemVersion.plist to recheck the correct system version (10.10.2).