THE PROBLEM WITH ADOBE SHOCKWAVE FLASH IS THAT IT ADDED IN A PROTECTED MODE - and 64 bit systems are not compatible with this protected mode which handles processes and memory usage differently. Flash already has sufficient security and protection - we are going to disable Adobe protect mode in Windows to fix Flash w/ 64 bit systems.

I strongly recommend this fix to anyone running a 64 bit system with Firefox being sluggish, slow, and having issues with unresponsive Flash Player Plugin and crashes. By the way I am using the latest upgrades and editions: Firefox 28 | Adobe Flash Player 12 Plugin version 12.0.0.77.

To stop the crashes you need to disable protected mode in Windows. This is very easy to do.

    Go to Start > My Computer (C:) > Windows > sysWOW64 > Macromed > Flash and double click it. 

    Find the mms.cfg (or mms file) and Drag it to your Documents folder where you can edit it without being bothered about administrator privileges; "ACCESS DENIED". 

    Open mms.cfg from Documents with Notepad. You will see: 

     SilentAutoUpdateEnable=1
     AutoUpdateDisable=0

    ADD, on a separate line (case sensitive): 

     ProtectedMode=0

    Save the file and close Notepad. 

    Hold down the Ctrl key and drag the mms.cfg file back to the Flash folder to make a copy there, keeping the original in Documents. 

    Restart Browser and Restart Computer. 


After applying this fix I tested it in Firefox: I had one window with 10 tabs open (regular websites) and a second window with 7 open tabs (CNN news videos, Facebook games, You Tube, Blog pages, etc.) each of which needed flash player. I switched back and forth between each open tab playing, pausing and scrolling the video forward with no delays.

Everything worked seamlessly without any hangups. My entire browser experience was much faster again; switching between windows and open tabs without any time delay whatsoever.