Duplex printing has stopped working.

[TonerBoner]

Posting on behalf of the Father In Law.

He has a month-old M479fdw along with a new i5 NUC build I built for him.

Auto duplex printing worked up until a few days ago. He's also getting a prompt that tray 2 is empty and to load paper.

Things I have tried (over the phone, due to Covid lockdown):

1. Re-loading tray 2 to full.
2. Changing the paper size in printer preferences and settings to A4 from letter wherever possible.
3. Inspecting all rollers in tray 2 and in the back access panel.
4. Ensuring duplex unit is installed in device settings and all paper sizes are set to A4.
5. Uninstalling the HP software suite through add/remove programs, and removing the printer from devices & printers.
6. Reinstalling the software and drivers through HP Easy Start.

On a multi-page document, it will start printing without issue - no more 'tray 2 empty' prompts. But now it only prints the first side of the first page and nothing after that.

I'm after some more suggestions for what instructions I can give him over the phone to try and fix this.

Thanks every. Stay safe.

[Repairatrooper]

Based on your description, you really want to make sure you do not have a hardware issue with tray 2. Have him try to copy a multipage document, if that works properly then likely the print engine is fine and you indeed have a driver issue. If multipage copying has similar feed issues then  it is more likely you have some sort of sensor or tray sizing error. Make sure that Tray 2 is set to the actual paper size that is loaded. The Any Size setting exists but should not be used if it can be avoided.