Known Issues On Microsoft Windows
You may not be able to print PDF documents from Mozilla Firefox if you have Adobe Reader 6.0 installed (bug 207417). Upgrading to Adobe Reader 7.0 reportedly fixes this problem.
Old versions of Adobe Reader have known security issues. All users should update to the latest available release.
Adobe Shockwave Player
On some Windows XP systems, the Shockwave plugin may not work unless Mozilla is run in Windows NT or 2000 Compatibility mode. This appears to be a Shockwave issue, not a Mozilla one (bug 225894).
Adobe Shockwave Player does not include support for Shockwave Flash (.swf) files. You will need to install Adobe Flash Player seperately to support these files.
It has been reported that calling Webservices via Flash WebServiceConnector may not work using the Shockwave plugin with Mozilla.
Windows Media Player
Using the Windows Media Player 9.0 control may cause Mozilla to crash on exit on Windows 2000 systems. This is triggered by having an old version of the Java plugin installed. [Bug 244713]. Upgrading to Java Runtime Environment 5.0 Update 4 or later will fix this problem.