Firefox 15 runs extreeeeeemly slowly on Windows 7
System:- Windows 7 v6.1 SP1 Intel 17-3770 CPU @ 3.4GHz 8Gb RAM Firefox 15.0.1
Firefox runs much slower than on my old Pentium3 PC!
On my old PC I found that Flash 11.3 caused so many Firefox crashes that I just could not play my favourite game on BBO and no amount of removal or down-grading of Flash solved the problem. I gave up and bought a new PC!
NOW I find that Firefox is so slow it is unusable!
Chosen solution
Hi Steve,
I have marked your troubleshooting post as the solution to the thread, it certainly worked for you.
I find this rather odd though:
Safe mode pointed to a problem with a plugin
.... I started Firefox in safe mode - Eureka!
Presumably by that you mean that you continued to have problems in safe mode ??! Safe mode will disable hardware acceleration, but safe mode will not disable plugins such as FlashPlayer. See
Also note that Adobe FlashPlayer protected mode is only applicable to Windows >= Vista, and not to old machines that use Windows XP.
Read this answer in context 👍 3All Replies (3)
Trouble shooting:-
I followed some advice I found in the support forum, particularly from:-
“Update to 15 caused computer to run really slow....”
/questions/935835 link added -J99
I reset Firefox to default settings – no change I disabled hardware acceleration – no change I started Firefox in safe mode - Eureka!
Safe mode pointed to a problem with a plugin so I followed section 5 of
- https://support.mozilla.org/en-US/kb/troubleshoot-and-diagnose-firefox-pr...
- EditGeneral link Troubleshoot and diagnose Firefox problems_5-troubleshoot-your-plugins
- 1st link is Mac on fx15, 2nd link should match a thread readers OS & fx version -J99
Further research led me to http://kb.mozillazine.org/Flash#Disabling_Protected_Mode_in_Fl...
Disabling Protected Mode in Flash 11.3 You can disable Protected Mode in Flash 11.3 (or above) by adding the line ProtectedMode=0 to the Flash "mms.cfg" file located in: (Windows 32bit) C:\Windows\System32\Macromed\Flash (Windows 64bit) C:\Windows\SysWOW64\Macromed\Flash For example, on a Windows 7 64-bit system, open the C:\Windows\SysWOW64\Macromed\Flash folder, copy the file "mms.cfg" to the desktop, open it in Notepad, add a new line ProtectedMode=0 and then close Notepad, saving your changes. Next, go back to the C:\Windows\SysWOW64\Macromed\Flash folder, rename the original file to "mms.cfgBAK" (to save it as a backup) and then drag and drop in the modified "mms.cfg" file from the desktop. [30] [31] [32] [33] [34] [35] [36] Note: To re-enable Flash Protected Mode, either restore a backup of the original mms.cfg file, if you saved one, or else re-edit the mms.cfg file to remove the ProtectedMode=0 line you added. Updating Flash Player or installing a newer version does not automatically re-enable Protected Mode. [37] [38]
This workaround has fixed my problem, looking forward to a version of Flash that works!!!
Hope this helps other folk Steve
Modified by John99
Chosen Solution
Hi Steve,
I have marked your troubleshooting post as the solution to the thread, it certainly worked for you.
I find this rather odd though:
Safe mode pointed to a problem with a plugin
.... I started Firefox in safe mode - Eureka!
Presumably by that you mean that you continued to have problems in safe mode ??! Safe mode will disable hardware acceleration, but safe mode will not disable plugins such as FlashPlayer. See
Also note that Adobe FlashPlayer protected mode is only applicable to Windows >= Vista, and not to old machines that use Windows XP.
Thank you for your help
My problem is solved