hello, i don't know if you want to stay with firefox 11 for the moment or further troubleshoot the issue. in the latter case, as a first step, please launch firefox in safemode once, see if the memory leak is occuring there too & report back with your findings... thank you!

Diagnose Firefox issues using Troubleshoot Mode

I may get around to testing 12.0 again at the weekend, but running without my Add-ons is like running IE9 which is definitely not what I want. I am not really sure as to what this is meant to prove. Even if it were an add-on causing the problem, then it would be showing the same symptoms under 11.0. If you can tell me the purpose behind running in Safe mode and what it would show, then it would make more sense to try it, but t really sounds like the advice one gets from Adobe or Symantec. Uninstall everything and re-install everything!!!!

hello, ok i will elaborate on my rationale. tackling memory leaks in the browser is a top priority of mozilla & there has been much progress has been made over the last months. such high memory consumption as you've described is most commonly caused by leaking addons & plugins nowadays...

therefore i've proposed to run firefox in safemode ONCE, in order to see what the result is (addons, hardware accelleration and incremental js-garbage collection are disabled in safemode, plugins stay active). even if it's working fine in firefox 11, maybe a combination of an addon & one of the many changes in firefox 12 is triggering the problem. i'm sorry if this is sounding like a generic troubleshooting advice, but frankly there isn't much else i can propose for the information available. we have to start somewhere...

(firefox 15 will contain vast improvements that should prevent nearly all memory leaks caused by addons, but at the moment it is still in early development and rather unstable, so i wouldn't recommend installing the preview version just yet - the release date is end of august).

OK, I got around to re-installing 12.0 and starting it in Safe Mode. It started at 251MB and crept up to 265MB over a period of 30 minutes and then stayed relatively stable. I then restarted 12.0 in normal mode with Add-ons active. After hitting 421mb it seemed to stabilise. I then went into each of my open tabs one after the other. In some case the usage went up and some it went down but all in all remained fairly stable around 450mb. At the moment I am unable to see anything causing memory creep. The question is what I need to do when I identify memory creep so that you have more information to work on.

At ca. 15:00 today, FireFox was automatically restarted after exceeding 800mb

this was during normal browsing, i suppose - which extensions have installed in tools > addons > extensions? (you can also enter about:support into the location bar and copy them from there...)

Here is the output from about:support:

Adblock Plus2.0.3 true {d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d}
Add-on Compatibility Reporter1.1 true compatibility@addons.mozilla.org
AnyColor0.3.3 true anycolor.pavlos256@gmail.com
British English Dictionary1.19.1 true en-GB@dictionaries.addons.mozilla.org
Bytemobile Optimization Client4.2.2 true ff-bmboc@bytemobile.com
Collusion0.16.3 true jid1-F9UJ2thwoAm5gQ@jetpack
DigitalPersona Extension5.0.0.3790 true otis@digitalpersona.com
FEBE7.0.3.3 true {4BBDD651-70CF-4821-84F8-2B918CF89CA3}
fireform0.7.4 true fireform@mozilla.org
FireFTP2.0.4 true {a7c6cf7f-112c-4500-a7ea-39801a327e5f}
Flagfox4.1.15 true {1018e4d6-728f-4b20-ad56-37578a4de76b}
FoxClocks2.9.38 true {d37dc5d0-431d-44e5-8c91-49419370caa1}
German Dictionary2.0.2 true de-DE@dictionaries.addons.mozilla.org
Ghostery2.7.2 true firefox@ghostery.com
IDM CC7.3.19 true mozilla_cc@internetdownloadmanager.com
IE Tab Plus2.0.0.0 true ietab@ip.cn
LastPass1.90.6 true support@lastpass.com
Memory Restart1.8 true memoryrestart@teamextension.com
Mozilla Archive Format2.0.6 true {7f57cf46-4467-4c2d-adfa-0cba7c507e54}
Night Launch Companion0.1.20120515.0832beta true nightlaunchcompanion@example.com
Norton Vulnerability Protection10.1.1.8 - 4 true {BBDA0591-3099-440a-AA10-41764D9DB4DB}
NoScript2.4.3 true {73a6fe31-595d-460b-a920-fcc0f8843232}
Print Edit8.4 true printedit@DW-dev
Skype Click to Call5.9.0.9216 true {82AF8DCA-6DE9-405D-BD5E-43525BDAD38A}
Surf Anonymous Free1.0 true support@surfanonymous-free.com
Tree Style Tab0.14.2012050301 true treestyletab@piro.sakura.ne.jp
VerificationEngine®2.7.0.37 true {E5C20E23-9BBF-4a06-AC43-277382EF1B43}
Wörterbuch Deutsch (de-DE), Hunspell-unterstützt20120211 true de_DE@dicts.j3e.de
WOT20120515 true {a0d7ccb3-214d-498b-b4aa-0e8fda9a7bf7}
Xmarks4.0.5 true foxmarks@kei.com
Adobe Acrobat - Create PDF1.2 false web2pdfextension@web2pdf.adobedotcom
Autofill Forms0.9.8.3 false autofillForms@blueimp.net
HP Smart Web Printing4.51 false smartwebprinting@hp.com
Norton Toolbar2012.5.4.6 false {2D3F3651-74B9-4795-BDEC-6DA2F431CB62}
WordReference Translator1.6.8 false {4095283b-2f11-42cf-a805-803c7001ffd9}

trying to solve a problem. If you are looking for answers to common questions
about Firefox, check out our support website.

hello again, so when the memory leaks are growing slowly during surfing i'd probably look at extensions that are potentially active on every page and disable them one by one - i'd begin with Skype Click to Call, VerificiationEngine & Bytemobile Optimization Client...

or if you don't want to troubleshoot extension, on tuesday next week the aurora version of firefox 15 will be released (it will contain fixes for common addon memory leaks). you can download it from: http://www.mozilla.org/firefox/channe.../#aurora

& probably not related to the issue: were you using Add-on Compatibility Reporter to force some addons to be compatible - since firefox 10 addons default to compatible, so you probably won't need it any longer...

Have disabled all three extensions as they are not really that important. Did not use the Compatibility Reporter since about Firefox 10. By the way the latest Aurora 14 on my Smartphone is a disaster and hangs continuously, so I hope 15 is better

Storage crept up to 557MB despite the fact that I closed 8 tabs. Storage is now fluctuating between 540MB and 560MB with a slow growth tendency.

Did you try a new profile without making any modifications?

Create a new profile as a test to check if your current profile is causing the problems.

See "Basic Troubleshooting: Make a new profile":

• https://support.mozilla.org/kb/Basic+Troubleshooting#w_8-make-a-new-profile

There may be extensions and plugins installed by default in a new profile, so check that in "Tools > Add-ons > Extensions & Plugins" in case there are still problems.

If the new profile works then you can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files.

See:

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Created a new Profile, but the amount of work involved with identifying and moving stuff is beyond my free capacity at the moment. Will possibly try at the weekend.