HP Officejet Pro 8620 - "An error occurred while communicating with the scanner. (-9923)" after upgrade to MacOS Sierra

This didn't fix it.

I have reset the printing system and deleted the contents of /Library/Printers

I have used the HP Easy Start App to install the printer.

Rebooted

Reset NVRAM

In the App Store under Updates I see HP Printer Software Update version 5.0

Just Command R'd and reinstalled MacOS Sierra. Still getting the -9923 error.

Booted into the recovery console and ran disk utility "First Aid"

Tried creating a new account and running Image Capture or just printer ==> scanner tab. This doesn't work. They all fail with the same error as in the subject.

Tried using Image Capture... no success.

Have received and installed several "HP Printer Software Upate" packages under the Appstore Updates section.

Updated my Printer firmware and rebooted both MacBook and printer.

inummerable printer system resets.

Now trying turning off disk encryption. (don't think this has a bearing on the problem, but just trying anything now)

checked logs in /var/log/* the error message

So in short the upgrade to MacOS Sierra has total broken the scanning functionality

Does anyone have any idea on how to do deeper investigation. That doesn't involve rotating between installing software from HP website and doing printer system resets that seem to be mentioned in many of the forums.

I am connected to the printer over WiFi and the printer is too. No problem printing.

Downloaded HP Utility and HP Easy Scan.

Been back and forwards through that document and keep getting the same problem....

Does anyone have any other ideas before I do an Option Command R and revert back to a version of MacOS X that is able to talk to my Scanner?

Just got this working. The fix http://jamesmcdonald.id.au/it-tips/macos-sierra-scanning-fail