Lexmark X644
This article outlines the steps for resetting the factory defaults on the MFP.
Resetting the factory defaults
Turn off the printer.
Hold down the 6, 7, and 8 buttons and turn on the device.
When the MFP displays Resetting Factory Defaults, release the buttons. The MFP will go through the reset cycle and return to the Ready Page.
LEGACY ID: SO4378
Here are steps to troubleshoot a 950.xx NVRAM Mismatch error code on the Lexmark X64x Series AIOs.
Cannot Clear the Security Password