Check if the flash drive is inserted into the front USB port.
Note: The flash drive does not work when it is inserted into the rear USB port.
Is the flash drive inserted into the front USB port?
Go to step 2.
The problem is solved.
Check if the flash drive is supported. For more information, see Supported flash drives and file types
Does the error message still appear?
Go to step 3.
Check if the front USB port is disabled. For more information, see Enabling the USB port.
Contact customer support.
Unable to downgrade code; Green Micro
Unable to 'Receive' a Fax with Laser Multifunction Printers (MFPs)