HP UPD - System Administrator's Guide HP UPD 5.6.5

c. Select the option to Always search file names and contents.
3. Search for hppscnd (within the files). If present, the search result will show one or more oemxxx.inf files.
4. For Windows 7, go to a command prompt (run as administrator) and type pnputil -d
oemxxx.inf. Remove all scan null drivers found in the previous step.
For Windows XP, rename all oemxxx.inf files found in the previous step to oemxxx.inf.old.
NOTE: If the file is in use, it means that other printers are using the same file, which have to be
deleted before the hppscnd files can be removed. These printers will have to be reinstalled/recreated
after the HP LaserJet 400 color M451dw product has been installed correctly.
After following the above steps, all scan null drivers have been uninstalled/removed.
To reinstall the scan null driver:
For Windows 7, you can reinstall the HP UPD 5.5 including the scan null driver with the command pnputil
–a *.inf.
For Windows XP, it is not required to reinstall the scan null driver.
Now disconnect and reconnect the USB cable to restart the Plug and Play installation process.
Alternative method for Windows 7:
1. Open Device Manager, and then click Imaging Devices. You will see one or more HP PNP Scan Null
drivers.
ENWW HP Laserjet 400 Color M451dw installed as an imaging device instead of a printer after plug and play
event on Windows 7 or Windows XP
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