Canon MB5450 Series Online Manual page 1173

250 An error has occurred.
Turn the device off and then back on.
Scanner driver will be closed.
252 Cannot write or read file.
1173
For how to delete MP Drivers, see
Deleting the Unnecessary MP
Drivers.
• Turn the device off and then back
on.
• Exit running applications, check
that there is sufficient free space
on the hard disk, then scan again.