So in situations that occur with regularity like you describe, the likely cause is some sort of software conflict. however without more specific data than we would want posted here on the forums it can be tough to say for sure. So I am providing some more general troubleshooting for issues like this.
First make sure Windows is fully up to date, rerun the update process manually, install any updates, restart the system and rerun the update. Repeat until it says no more updates.
Then upgrade your system drivers via the system or motherboard provider as well as any hardware drivers for GPU, Audio, Network from the maker for that component.
If you have any addon managers installed. They are fine programs but they have the tendency to prevent our troubleshooting steps from working. Please uninstall them and leave them off your system until we have solved the problem.
Once that is confirmed, we need to delete the temporary game files to attempt to eliminate any corrupt data that might be affecting the client or characters. Your game will rebuild them when you next login but this will remove all installed addons. Please do not reinstall any addons until we know the issue is resolved: https://battle.net/support/article/7549
Let’s reset the in game user options:
- Click the blue bnet icon on the bnet app.
- Choose settings, then game settings.
- Click the reset in game user options button under the correct game listing.
- Confirm the changes and close the window.
We will want to run the repair tool on the game client: https://battle.net/support/article/7655
Try running your system in selective startup mode: https://battle.net/support/article/200483
Create a new administrator account: https://battle.net/support/article/34550
Once the account is created, shut down the computer, wait 60 seconds, restart, log into the new profile and try the app/client.
If that doesn’t solve the issue, submit a ticket making sure to include the requested system files.
https://us.battle.net/support/en/help/contact/1461/ticket