Aristois

@lknotok omfg I just realised I accidentally turned on name protect
It's confirmed: I am dumb.

@dyiing turns out that was the cause of it, but i need it to record some of my gameplays while i play on my friends server. is there a way to get it working with replaymod?

@lknotok navigate into GUI and find thisjavaw_CKgs25OF7O.png

I believe that only deleting the .minecraft/mods/optifine.jar is necessary to fix this issue. If you delete that and it still doesn't work, then the url above mentions how to completely uninstall OptiFine.

It happens because the optifine.jar is shared in the .minecraft/mods/ folder between versions, so if you run optifine on multiple versions it will keep overwriting it, or causing an error since it's not the right version.