So, after upgrading to Windows 10, my printer driver seemed to forget it's duplexer settings.
It has an automatic duplexer installed, so that I can automatically print double-sided. Great invention, and good for when I'm printing documents off for Clay Cross Model Railway Society.
So, it's more than a little irritating to have it disabled every time I print something.
Not sure who to blame. Microsoft are pointing the finger at HP, but the same driver worked just fine on Windows 7.
After following instructions on Microsoft's Community page (link) it was still suffering from duplex amnesia. I thought to myself, I can find a better solution.
So, I re-installed the driver again (fourth time), from scratch, and then found out where in the registry it keeps all it's settings. Google helped here.
I exported the key out using regedit, and then went into Word, and enabled the duplexer through the printer settings, and left it hanging, ready to print. I then took another snapshot of the same registry key, and compared them in WinMerge, an absolutely amazing compare tool I've used at work when doing code reviews.
It highlighted a few differences relating to the duplexer, so I just modified a batch script I run at logon (also clears out temp files, xcopies some data files, and so on) to re-import the duplexer-corrected registry key.
Restarted, and BAM... problem solved.