your patch progress bar is stuck on "Applying Patch", please give it at least 5 minutes. It is likely that there is activity occurring that is not registering on the progress bar. If the progress does not begin to move after 5 minutes, close the launcher completely and reopen it.
Any modifications to the game files can cause this issue. If you have made any modifications to your game files you will need to replace the unmodified files or re-patch.
If this issue continues, perform the following steps: