FAQ: I'm having trouble installing Flash Catalyst CS5, how do I clean up beta installations?

Question

The majority of users have trouble installing Flash Catalyst CS5 when they have not properly run the uninstaller on a previous version (typically a beta version).
If this is the case, the first thing you should try is running the Adobe CS5 cleanup script: http://kb2.adobe.com/cps/829/cpsid_82947.html

Answer 1

Flash Player Protected Mode provides a modern, sophisticated set of security protections that we see as critical in today's security landscape. 
We highly recommend that users not disable ProtectedMode.  Also, it's worth noting that by manually changing your mms.cfg, you have opted out of Protected Mode for all future versions of Flash Player, as we will continue to honor that preference. This puts your system at risk, and that risk will continue to grow over time. 
Ultimately, this is an issue with the RealPlayer Browser Record plug-in.  There is a more technical explanation in the Mozilla bug referenced above in the thread, but the simplified version is that the security enhancements designed to prevent the introduction of malware via Flash Player make RealPlayer Browser Record plug-in no longer compatible with Flash Player for Firefox.  You can disable the record functionality to eliminate this issue, while retaining the ability to view both Flash and Real Player content.
To disable the Real Player Browser Record functionality while maintaining the enhanced security provided by Flash Player with Protected Mode, do the following:
    Launch RealPlayer
    Click the RealPlayer icon in the upper-left corner of the window, and choose Preferences
    Choose Download & Recording from the left-hand menu
    Uncheck "Enable Web Download & Recording for these installed browser"
    Click OK