Hello
Are you upgrading from Windows 10 to 11?
How much free space do you have now on your C drive?
Don't just delete your files yet in Documents, Pictures and Music files, as the deletion can sync to your OneDrive and delete them there too. Instead, go to your OneDrive app settings (lower right cloud icon) > Settings > Sync and backup tab > Manage backup, turn those folders off first. Then restart the computer and then you can delete the locale files safely.