If you are having a printing problem with an HP LaserJet 6L on Windows 10 for the first time, it could be the drivers. When a client contacts me regarding this printer on Windows 8, the first thing I ask them is ‘Where did you get the drivers?’ and is told that Windows 8 installed it for them once the USB cable was connected.
Unfortunately, when Windows 10 automatically install drivers for the HP LaserJet 6L, it may install incompatible drivers so you will want to manually add the drivers from HP’s website before connecting the HP LaserJet 6L printer. As a rule, you should always install the drivers first then connect after a restart or connect when the printer’s installation software prompts you to do so.
One option is to have it powered off (if it have a power button) while the data cable is connected. The second option is to have it on (so you can set any language, time, etc) but the data cable is not connected to the computer. Keep this in mind if you must reinstall the drivers or the Operating System.