Every time i log on a character, after the loading bar reaches 100%, the game gets stuck for like 10 sec, sometimes i get the “not responding” error, sometimes the game just closes without any error
Loading screens issues are usally add-on related. Try disabling all addons and see if the issue continues, if not then it’s one or more of your addons causing it.
I tried without addons aswell, it’s the first thing i thought about
On first step, i would run a checkdisk on ssd/hard drive, then scan and repair wow files.