MT65xx was preloaded on my Mac Pro

If this is a used, open box or refurbished Mac Pro, then it was not properly prepared for resale.

see > What to do before you sell, give away, trade in, or recycle your Mac - Apple Support

If you can not erase, reinstall and setup as yours, then you need to contact the seller for help or a return.

That sounds like the Mac Pro was either not purchased new or was not reset before you purchased it. There may be possibly other applications installed on the computer that you are unaware of and may be undesirable. I would suggest resetting to Factory Settings if that is true to wipe the computer and set it up as yours.