Getting the Duplex Attachment to Work with Vista

is your version of windows 64-bit or 32-bit? The drivers need to match the exact version of windows

upd-5_1_1_8232-pcl5_winxp-vista-x64.exe [1/1, 15.21M] System requirements: Client and server operated systems supported for the most current release of the UPD:
Client operating systems supported:

• Microsoft Windows 7 Starter, Home Premium, Professional, Enterprise, and Ultimate; x86 and x64
• Microsoft Windows Vista Business, Enterprise, Home Basic, Home Premium, and Ultimate; x86 and x64
• Microsoft Windows XP (SP2 and later) Home Edition, and Professional; x86 and x64
  *Note: Microsoft retired mainstream support for Windows XP in April 2009. HP will continue to provide best effort support for the current UPD and tools for the discontinued Windows XP operating system until 2011

There are none and I am sorry but there probably never will be, See this is the major problem with Win 7 anything over a year old generally just isn't supported.
Here is how to Install them so they work. Download your XP driver you wish to install. If it's in a zip/rar file then extract it to your desktop. You should have a simple .exe file sitting on your desktop to install the drivers, as normal for XP. Right click the .exe file and select "Properties". Then select the tab called "Compatibility" Now check the box next to "Run this program in compatibility mode for:" Make sure "Windows XP Service Pack 2" is highlighted. Now apply the settings and run the installer. This should work for most drivers, but not all Install and run as Administrator.

Hi, Please find the work around steps to resolve duplex printing issue in Windows Vista. Please the send the *.gpd files to the cu via mail before doing the steps. Duplexer Printing for Windows Vista Troubleshooting steps 1.start-all programs- accessories ? cmd -right click-run as administrator 2.Stop the Spooler service - Type net stop spooler 3.Change current directory Type cd windows\system32\spool\drivers\w32x86\3 4.Backup the old gpd files - Type copy hp*.gpd *.bak 5.sent the zipped file to customers email address through astro and then download the file to customers desktop 6.extracted the files from the zipped folder and then pasted those files to windows\system32\spool\drivers\w32x86\3 7.Remove old BUD file Type - del HP*.bud file 8.Restart to spooler service - Type net start spooler 9.checked under printing preferences if the both sided printing is selected as automatic and then tried printing a two page document 10.checked whether its printing or not. 11.) Start-Control Panel- Printer & Faxes- Right Click On the printer -Properties-Device settings-Disable the manual Duplex printing-Click on Installed Two sided printing-click on apply & ok. 12) Then Go to Right Click on the Printer-Printing preferences-Paper quality-Select Two Sided Printing from the top drop down list where its showing What do you want to do? 13) From Print on both sides-Select Automatically from the drop down list. 14) Try to print on both side check whether its working or not.

It' also listed at Microsoft as incompatable with vista. Best you can do is get a cheap old used machine that runs XP and set it up as a print server for your network, (set it up with printer sharing) send all of your documents thru it for printing. Sorry it's probably not the answer you were looking for but it is the only solution I've found for mine. I bought an old P3 machine running XP for $5.00 at a garage sale and it's working great as a print server.

vista can not work on those older systems. change it to xp-os, then re-load the printer driver software.

This is a non Vista compatable product.
It may run on Windows Vista 32bit Business though.

Join the Alps mailing list at YahooGroups. The drivers are in the files section.

http://tech.groups.yahoo.com/group/Alps/

Check for new drivers(for your printer) or upgrade, for windows vista....Sometime the driver for windows xp is not the same.

THIS SOLUTION IM ABOUT TO TELL YOU IS IN MY EXPERIENCE THE EASIEST ONE JUST DOWNLOAD THE WINDOWS XP DRIVER FOR THE HP DESIGNJET 450C PRINTER AND INSTALL IT INTO THE WINDOWS PRINTER PLATTFORM, YOU MAY SEE SOME ANOUNCEMENTS FROM YOUR COMPUTER TELLING YOU THAT THE PROGRAM YOUR TRYING TO INSTALL MAY NOT BE COMPATIBLE "DONT LISTEN TO THEM" JUST CONTINUE YOUR INSTALLATION AND PRESTO YOUR DESIGNJET PRINTER WILL WORK PERFECTLY