İ’ve been trying to play Classic on windowed mode for the last few hours and I’ve been getting “Unable to start 3d Accelerators” error every time I tried. I redownloaded wow, deleted and updated my graphics card drivers.
https://eu.forums.blizzard.com/en/wow/t/cant-run-classic-in-windowed-mode/75144/5
Turn off any overlays such as discord etc.
All of them are deactivated
mhhh
first of all have you tried to change those settings in the login screen / character create / select screen ?
Second of all do you have any info about your OS and GPU ? and are drivers up to date ?
I get this sometimes too, but not always. I also find that classic drops to 30fps after ~5 seconds when fullscreen (I have a potato-eating monster of a PC so it’s not that) but stays at 60fps if run windowed with the window stretched to fullscreen. I have never had an issue with regular WoW in 15 years of play.
I fixed this exact problem by going in WOW install folder, making a shortcut for wow.exe and then running it as administrator. Using windows 10 btw.