If you are experiencing KRNL crash errors on Roblox, the following steps can be helpful:
Make sure that your computer meets the minimum system requirements for the game. If you’re using an older computer, upgrading your hardware may be necessary. Update your graphics drivers and install any available updates for Windows. If the problem persists, try resetting your graphics settings to the default values. If all else fails, you can try reinstalling Roblox. This should only be done as a last resort, as it will delete all of your progress in the game.