Try going to Settings, Shared Cache Settings and run Verify. If that doesn't help, try the Fix permissions from the same dialog.
If that still doesn't help, open up the shared cache folder. You can do that from the E menu, Find in Explorer, Shared Cache. Delete the tq folder and restart the launcher, let it rebuild the folder from scratch. Don't worry, settings are not stored in there.
CCP Snorlax - Software Architect - Team RnB - @CCP_Snorlax -
http://ccpsnorlax.blogspot.is/