Multiple instances of plugin-container.exe begin on exit.
When I exit out of Firefox I noticed (lately) that multiple instances of plugin-container open for a few seconds then all close together. At last check it appeared to be like 12 separate processes running. It keeps growing until they all shut down when firefox.exe does. Any clue why this is happening?
Krejt Përgjigjet (2)
Can be caused by using Delete browsing, search and download history on Firefox, so if you use that then try to find out which setting (cookies?) is causing it. Firefox 4 also clears Flash cookies, so might be using the Flash plugin to achieve that.
The number of plugin containers launched is related to the *total* number of add-ons installed, including all the disabled ones! I had about 10 disabled add-ons (and plug-ins) in my Firefox 8, which made it painfully slow to exit Firefox, because of all the spawned plugin-container.exe processes. Once I removed all the disabled add-ons, it got much quicker.
Unfortunately, the add-on manager is not very helpful in uninstalling disabled add-ons, most don't have an active "uninstall" button at all. To make matter worse, there are lots of different ways how add-ons can be integrated into Firefox, so it takes a lot of searching to find all the unwanted ones.
Here are the places I had to visit on my (64bit) Windows Vista PC:
C:\Program Files (x86)\Mozilla Firefox\extensions: each subdirectory is an add-on. Have a look inside the install.rdf in each folder to see what they are. Remove directories you don't want.
C:\Program Files (x86)\Mozilla Firefox\plugins: each np*.dll file is an add-on. When you hover over the file in Windows Explorer it will often print some details like the Vendor. Remove files you don't want
C:\Users\<username>\AppData\Roaming\Mozilla\Plugins: same as above
C:\Users\<username>\AppData\Roaming\Mozilla\Extensions: same as above
C:\Users\<username>\AppData\Roaming\Mozilla\Firefox\Profiles\<random-string>\extensions: the directories here work like \Extensions above, i.e. check the install.rdf inside. The *.xpi files here can be opened in a ZIP program (I use 7-zip) to look at the install.rdf inside them.
In the Windows registry (launch regedit.exe):
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\MozillaPlugins
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Mozilla\Firefox\Extensions
HKEY_LOCAL_MACHINE\SOFTWARE\MozillaPlugins
HKEY_CURRENT_USER\Software\MozillaPlugins
Just remove the ones you don't need.
And as the last place, type about:config in your browser address bar and then search for the string "plugin.scan": to disable plugin scan set the value to an unreasonably high version. For instance, I set my "plugin.scan.Quicktime"="99.0"