This is a CRAZY situation!
ALL printers that worked before the upgrade have stopped working. After printer reset and de-installation, then installation of printer drivers, within the Yosemite OS, tried to print.
System reports that the print worked OK, found the printers on the network etc. then I went to the printer and nothing was there!
According to Yosemite the print finished fine! Clearly the printed document just went into the ether!
It's almost like going back the early 90's with Linux! Not the 2014's with the world's supposed most sophisticated software (actually Unix, but close enough).
Why do Apple issue upgrades like this without testing them properly!
I've decided to take this to the local courts on a "not fit for purpose" basis.
SMB