Starting TBC classic results in Windows 7 Aero theme being disabled and forcing Windows 7 basic theme . This results in me being unable to full-screen my windowed wow.exe without seeing the windows tool bar. Additionally, desktop VSYNC is disabled under Windows 7 basic theme; it is not possible to override at the application level using NVIDIA control panel. I have verified this with vsync tearing tests. GPU memory is not an issue, as I am running a 6GB 2060. I had no problems prior to the TBC classic patch. The same bug was listed on the US forums:
100% not because of that. Be it Cache, VRAM, RAM or GPU RAM all LOTS available. It started exactly right after the update today & ONLY when i start WoW classic.
I don’t know if it still exists in wow classic but does it have a true fullscreen mode? IIRC in windows 7 aero is disabled if you run games in fullscreen mode.
I merged yours with an older thread to try and keep the info in one place and since it’s still relevant. You’ll find steps to try and fix this linked in the first post here.