Okay, if the above doesn’t work, let’s fixate on one thing at a time, In the battle.net app click on the gear cog next to the Install/Play/Updating button and select the Scan and Repair option.
Allow it to scan, it will scan the whole installation and attempt to repair any corrupt file/s and re-download them if necessary.
If that doesn’t work; close off Battle.net entirely so that it’s not running in the background. Delete the Cache folder within World of Warcraft_retail_, this will cause Battle.net app to update, once it finishes try to play the game.
Next, we will look at DugiGuides Installer, load up the installer and click on Settings. Next, click on the Repair button.
Warning: this will remove all settings and completely resets the addon to its default settings across all characters.
If the suggestions don’t work for the Battle.net app then you might have to create a ticket with Blizzard.
Click the Battle.net Menu logo, top left corner of the battle.net app, click My Account, Click Support top right of the web browser window that opens, click on the Technical option, click the Contact Support, type the issue you’re experiencing with Battle.net where it keeps updating whenever you update/install addons etc.