Fixing "An unexpected internal error has occurred" with a sucky-sucky HP ScanJet 5550c Scanner

I'm documenting a fix to the "An Unexpected Error Occurred" that has plagued some HP ScanJet scanners.  This fix is for one specific cause of the error message.  There are fixes for other causes well documented online. 

The full error message reads "An unexpected internal error has occurred.  Close the program and then try one of the following: - Restart the program. - Restart the PC and then try again. - Reinstall the scanning software and then try again."  This error appears when attempting to start a scan using the HP Director software or when pressing the scan button on the scanner.  Scanning from any other application works fine with no error messages.

In my specific case, this was caused because the scanner driver was updated from 2.2.2.1 to 8.0.0.0.  8.0.0.0 came from the HP website when I downloaded the latest version of the software to install in on a computer that was having problems with the scanner.  2.2.2.1 was the original version that shipped on the CD with the scanner.

It turns out to not be very intuitive to downgrade the driver from 8.0.0.0 to 2.2.2.1.  Uninstalling and reinstalling the software doesn't do it.  To accomplish this task, open Device Manager with the scanner attached and turned on, double-click on the icon for the scanner and click on the Driver tab.  If you are suffering from this problem you will see the driver version is listed as 8.0.0.0.  Click on Update Driver and then you can hunt around for the correct driver.  I was able to find one that was already listed in my available drivers on my system.

Companies who build scanners, printers, or cameras (I'm looking at you HP) should not be allowed to write software!