This is usually caused by corrupted cache files or conflicting addons. Navigate to your installation folder, completely delete the Cache and Interface folders, and restart the game as an administrator.
To run a Legion 7.3.5 client, your system should meet these general requirements: [Repack] Single Player Project - AshamaneCore (Legion)
: Ensure you have a secure, lightweight torrent manager installed, such as µTorrent, BitTorrent, or Deluge.