You may try this, initially on the troubled PC where it hurts the least:
Redo the CS4 installation, using the Clean Script, http://www.adobe.com/support/contact/cs4clean.html.
This might end an unfortunate lingering of a pre CS4 printer setting.
Well, gave the clean scrip a try. No luck.
Not suprising since it didn't find anything I guess. Though I did notice when I reinstalled that my workspace was still there. Perhaps it missed something?
So still getting single sided pages when printing double sided. Any other suggestions?
Well, hurry it up, would you, Jacob?
Soon it will be 2010. We'll all be a year older, more of us will be out of work, AI 15 will arrive, and you'll be five versions behind.
Try this go to the System Preferences>Pinter and Fax in the printer lis remove your printer make certain that all your applications are not running except the finder.
Okay now go to User/Username/Library/Preferences/Adobe Illustrator CS 4 Settings and trash that settings folder and then lower down com.adobe.illustrator.plist as well and the n even further down there should be a preference for our printer trash that as well.0
Now go back to the Printer list and add your printer back now try to print.
You are right, as always, but I have stopped counting, unless I have to; then I start by remembering my being born in the first year under the present Queen. And some age with grace, including 10 and her face.
I believe I will stop pondering for now, waiting to see whether post #5 does it.
Well good try Wade, but still no luck. I am still getting 2 single prints... It is almost like AI is telling the printer there is a blank page between each artboard or something. Because the printer is getting the doubled sided command and acts like it will print double sided. It just doesn't print anything on the second pass. Thanks for trying though! There is still 1 computer that will print double sided, and suggestions on what to look for there that might have been done different? I have checked the printer drivers, and they are the same version.
Then you can try two things one is create a new user account and log in to see if that works.
then you can re install the printer driver and illustrator in the same order that you did on the computer that works.
Make certain you remove the printer from the printer list and trash botht he preferences an settings folder for the printer and illustrator before reinstalling.
Or perhaps your settings in the page set up is screwy from the print dialog access the page set up and make certain you have your printer selected and the right pages. Then in the print dialog make certain that you have defined by drivers.