You need to run the launcher as an administrator so it can update the game files on your hard drive. Run SW:TOR and the launcher as an administrator SWTOR on Steam uses a direct download launcher we call the Steam launcher. Open your launcher and look for the letters ST at the bottom left:
There are different versions of the launcher, identifying yours will help you troubleshoot any problems you’re having. If you’re getting an error code in the launcher, use CTRL + F to search for the code on this page. If you’re having trouble launching or patching STAR WARS™: The Old Republic™, check here for a solution.