Adobe has tested Acrobat 9.x (Standard, Pro, and Pro Extended) on Microsoft Windows 64-bit operating systems. Acrobat 9 is a 32-bit application that was tested on Windows Vista x64, Windows XP x64, and Windows 2003 Server x64. Microsoft Windows 7 Starter, Home Premium, Professional or Ultimate or Enterprise 64-bit is supported after the 9.2 update has been applied.
A known issue in Windows 64-bit operating systems affects 32-bit printing applications running in these 64-bit environments. This issue affects the Adobe PDF printer.
Microsoft has resolved this issue with Microsoft hotfix #930627. This hotfix was included with Windows XP x64 Service Pack 3, Windows Vista x64 Service Pack 1, and Windows 2003 Server x64 Service Pack 2 and does not apply to Windows 7 installations. For more information about this hotfix see http://support.microsoft.com/kb/930627.
Note: Because the Adobe PDF printer does not function properly without the Microsoft hotfix, Acrobat 9 checks to see if this fix is installed. Acrobat will not install unless the check confirms that the fix is installed.