Are you getting a (e.g., "bootstrapper error", "injection failed")? Which antivirus are you using?
Add an exclusion in your Windows Defender/Antivirus for that folder. Common Issues krnl_bootstrapper.rar
Restart Roblox and check if a new update for Krnl has been released. If you're having trouble setting this up, let me know: Are you getting a (e
I can provide troubleshooting steps or ways to whitelist the file. Are you getting a (e.g.