Hello I have two computers that were running Windows 8.1 and sharing a HP LaserJet 2100 printer. One was running Windows 8.1 x86 and one Windows 8.1 x64. Both were using a PCL6 driver. I upgraded both to Windows 10. After the upgrade the one running Windows 10 x86 could still print to the HP LaserJet using a PCL6 driver. But the one running Windows 10 x64 could not (no error but nothing would come out), and opening the printer properties dialog I would get a message complaining about the driver HP LaserJet 2100 PCL6 driver missing.
I therefore attempted to manually install the missing PCL6 driver using the standard printer properties dialog but got an error message telling me that a policy prevents NT 4 drivers from being installed. Ethernet Driver Missing Windows 10 on this page. Eventually I downloaded the HP Universal Printing PCL 5 driver directly from HP website and this one worked. While I can now print from both computers I am somewhat bothered by the fact that I have to rely on a PCL 5 driver when I could use a PCL6 driver with Windows 8.1. Is PCL6 not supported by Windows x64? What is this policy that prevents NT 4 drivers from being installed? Hello Guru Kiran After some digging I learned that Windows printer drivers can be either 'user mode' or 'kernel mode'. Furthermore I learned that Windows 10 disallows kernel mode printer drivers (aka Windows NT 4 drivers) by default using a group policy.