This is head up for any of you running into this issue. The Threshold 2 / 1511 Windows 10 update breaks parallel ports, causing printers and other LPT devices to stop working. I ran into this for the second time last night and after some searching found that this is a known Microsoft issue. In both instances everything worked fine until the update.
See. https://answers.microsoft.com/en-us/windows/forum/windows_10-hardware/windows-10-and-parallel-port-lpt-printer-doesnt/4f3ab63c-d6c6-4815-bff2-65c8ad6357d1?page=2&auth=1
The work around is to make any change to the port settings in device manager and then change back. This is temporary and the port will lock again after a system restart.
See. https://answers.microsoft.com/en-us/windows/forum/windows_10-hardware/windows-10-and-parallel-port-lpt-printer-doesnt/4f3ab63c-d6c6-4815-bff2-65c8ad6357d1?page=2&auth=1
The work around is to make any change to the port settings in device manager and then change back. This is temporary and the port will lock again after a system restart.