Occasionally you may need to remove a kext (or driver) which is not needed any more for the newest version of OpenCore or which has been replaced with another. Deleting kexts in the Kernel -> Add section will remove them from the Config.plist, but not from the disk. Since OCAuxiliaryTools automatically syncs changes on disk with the kext list in Config.plist, it is easier to just delete them from the disk. From the Kernel - Add section select Menu -> File -> Browse to show your current kexts in the Finder. Then delete any outdated kext.