If you get the Failed to create directory message with error=3 when starting Roblox on your Windows PC, use these proven fixes.

Now the AppData folder will appear. Go into the Local folder to find the Roblox folder. Delete the entire Roblox folder. Run the installer as Administrator.

If KRNL-Injector failed to find the Roblox process, delete KRNL App data and see. If that doesn't help follow the solutions mentioned in this post to resolve the issue.

For the most part Roblox works pretty well, but sometimes you get errors like ‘Failed to Download or Apply Critical Settings.’ Figuring out the problem is a bit of a head-scratcher. Regardless ...