To alleviate recognition errors with the HP 940xl cartridges, please try the following steps below. Should it fail, please call our customer service department at 1(888)321-2552 and we can assist you further.
(1) Remove the problematic cartridge from your printer
(2) Turn off and unplug your printer for one minute
(3) Using a Qtip and rubbing alcohol, gently wipe down the metal contacts on the inside bottom portion of the cartridge to ensure a clean connection
(4) Plug printer back in, power it up, and once prompted re-install the cartridge
(5) Try to print a document
Answered on 6/26/2014 by Valentina