Trying to deposit an item into the gbank will lock your character out of the world.
Must ALT+F4 to do anything.
Trying to relog will give you the “Character with that name already exists” error.
You can log in with another character and see your previous character(s) stuck in front of the gbank.
The character will “unlock” after ~3 minutes.
I am getting this exact same bug.
I can’t even access my Gbank. Just says I’m not in a guild despite being the GM.
Having this exact same problem. My priest gets locked out of everything after accessing the guild bank. Cannot make a deposit or withdrawal. Cannot cast a spell, cannot interact with NPC’s, cannot mount, cannot enchant an item. Log onto my mage and get told she is not in a guild, when clearly she is… the same guild for 10 years or more. She can pull up the guild roster too. Please fix this Bliz!
I have 3 characters stuck right now because of this. It’s taken well over 15 minutes to unfreeze them too. Gotta love patch days 
Same thing here. Even with all addons disabled and even tried deleting the wtf file.
This is still ongoing BTW.
Yup, still going on. When character gets locked after accessing guild bank I can’t even exit the game, have to force quit. Blizz you were doing so well with new patches but these last two have been full of bugs. I’d rather wait for excellent, working content than have you rush to put it out and have a bunch of things that don’t work!
This is still happening this morning. Very frustrating.
here is how I fixed my guild bank problem. Enable addon Bagon Guild Bank, and it worked for me.
Interesting. Bagnon’s Guild Bank DOES work. Good catch.