today i will show you how to fix the anoying World of Warcraft Startup Problem „Failed with an internal error“. Also problems with a WoW Launcher loop could be fixed with my method. After testing different solutions from different forums, i tried it on my own and so i found a solution, which works 100%.
In general the following steps will completly reset all your settings and reintall World of Warcraft but without a long download period or a reinstall by DVD.
1. Step: Create a Backup of your complete World of Warcraft folder
2. Step: Delete all files and folders in your World of Warcraft folder except the „data“ folder
3. Step: Go to your „Programs“ and „ProgramData“ folder an delete all „Blizzard“ or „Battle.net“ stuff in there. These folders shouldn’t contain import data, so they will be recreated be the following WoW Installer if they are needed.
4. Step: Download the WoW Install Client (only a few megabytes)
5. Step: Start the install and select your old World of Warcraft folder (important!), where only the „data“ folder is present.
6. Step: Wait and see how the installer check your files and only download all the small files which were deleted. This should only last a short time.
7. Step: When the install is done and your WoW starts up correctly, you can try to copy your „WTF“ and „Interface“ folder back from your backup. Please create a backup of your fresh „WTF“ and „Interface“ folders before. If there is a problem after the recovery you can still use them to startup your WoW correctly.