deleting all files in appdata\local\curseclient (or whatever it is named) worked for me. No crashes.

I was having the same problem and I deleted all files in the Users\[username]\AppData\Local\CurseClient folder and this seems to have fixed the crashing problem.  You will however have to resupply login creds

It sounds like one of the files is getting corrupted somehow.

Same issue with me.  Login and it locks hard.  And I'm on Linux/Wine. Ah, I see.  It seems to be getting hung on "Updating latest client", even though I disabled that option before login.

omg i got the same thing and i wanna install a new addon...