If you're struggling to get into World of Warcraft at the moment due to an error message beginning “The CAS System was unable to initialize”, then you're not alone. It seems that a problem that cropped up a few years ago has reared it's head once again in the new Legion expansion, and it's keeping many a player locked out of the game today.
While there is a community-sourced workaround available for solving this problem - and it appears to have fixed the problem for many, many people - Blizzard does not endorse changing the command line in this way. It goes without saying, then, that you undertake this fix at your own risk, and you may prefer to wait for Blizzard to resolve the problem themselves.
With that caveat out of the way, and if you really can't wait to log in for a moment longer, here's one reputed method for fixing the CAS System initialisation error:
CAS System error workaround
- Open the Battle.net launcher on your PC or Mac
- Make sure World of Warcraft is selected, then go to Options in the main window and select Game Settings.
- Scroll down to WOW and check the box called "Additional command line arguments"
- Enter the following into the new box that appears: -uid wow_engb
- Hit the big blue Done button in the bottom right to save the settings
More great WOW Legion guides:
If the fix works, you should now be able to log into World of Warcraft without any problems. If it doesn't, we'd recommend undoing the above steps and waiting for an official fix to be applied to the launcher or the game by Blizzard.
Personally we'd recommend waiting for things to be ironed out at Blizzard's end - they're aware of the problem, and actively working to solve it! We've also seen a mixed reaction this workaround, with some saying it works a charm, and others saying the problem persists.