From reports at Ghacks, it appears that the Adobe Flash Player update including Flash Player Protected Mode for Firefox is causing Firefox to freeze or crash.The addition of Protected Mode is for users of Firefox 4.0 and greater on Windows Vista and higher. (Protected Mode for Firefox is not available on Windows XP.) The purpose of Protected Mode is to limit the impact of attacks launched from malicious Flash content (SWF files).
If you experience crashes or freezing of Firefox after installing the latest Adobe Flash Player update, protected mode can be disabled as follows:
- The easiest solution is to disable the Flash Player Plugin. Select Add-ons > Plugins. Scroll through the list of plugins to "Shockwave Flash" and click "Disable".
- Follow the instructions provided by Adobe: How do I disable Flash Player's protected mode for Firefox?
- As some of the reports indicate the crashes occur if multiple pages with flash content are opened at the same time on Firefox, consider NoScript, which provides the ability to selectively allow Flash content.
Due to the critical nature of the Adobe Flash Player security updates, it is recommended that the update be installed. Adobe claims that the feature is fully tested and reliable.