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Multiples tabs problem since the last update

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Hello, please forgive my language since it's not my native one, I hope it will be understandible...

Since the last firefox update, I've got an issue with my tabs. I use a lot of them (3000+) and it wasn't a problem until now : when I started my computer, firefox launched all the tabs of my previous session, but they loaded only when I selected one of them. I could still launch other program, play games etc

Now when I launch my computer, my memory is sucked dry by firefox (50% to 80%), firefox take a massive amount of time to launch and load my previous session (5 secondes before update, 5-10 minutes now) and I can't use it without some serious lags. If I try to open new tabs it's getting worst and worst. I've try to restart it, repair it etc, but when I try to reload my tabs with a backup, the same issue happen again...

Does someone has an idea to fix this ? Or what the problem can be ?

Modified by ptipersobonus

All Replies (7)

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hello pt,

have you tried toggling/tweaking the hardware acceleration feature and the cache, inside of FF options "performance" section?


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After some experiment, when I toggle "off" the hardware acceleration feature, Firefox load and launch a lot faster (1-2 minutes), but my memory is at 60% constantly (got 16GO of RAM)

With the acceleration "on" the loading time is massive (I've kill firefox with task manager after 8 minutes of loading)

If by cache you mean the "number of content process limit", this number don't seem to impact my launching time but the loading of each individual page (when I click on one tab) is much stronger the less the number of process it is (which seem normal to me)

In each case my processor goes to 100% when firefox lauch (and it wasn't the case before the update)


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hello pt,

Thanks for the information !

I think what you may be experiencing is known as a memory leak. But this is only one possibility and may not be the actual case for you.

So the next thing to try is to disable all programs that are pre-launching with the windows desktop.

if you do a Start > Run > Msconfig or open the task manager Startup section, please temporarily disable everything that is enable. If a mouse or keyboard driver is listed, then leave these enabled.

Incidentally, can you tell us what version of windows you have and bit size? What is the amount of your ram and the size of your page file?


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It's done, everything except keyboard and mouse has been desactivate. I try to restart my computer and nothing change.

With the setting "no acceleration" and "8 process" > 100% processor until total loading to 10%, which take 1~2minutes > 60% memory taken)

- my computer run on windows 10 64bits

- it has 16GO RAM

- the file I use to restaure my session ("recovery.jsonlz4" in "sessionstore-backups") is 7 810 Ko

Thanks for your help, more than the solution, it's the why it happen that's concern me the most. I've try to close a quarter of my tab but its doesn't help firefox to launch and load faster.


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hello pt,

it looks like your computer is similar to mine.

but i do not have the issues that you have.

so i am leaning that Firefox is not the problem.

but instead, something with your o.s. or machine is being a problem for Firefox.

incidentally, what is your computers page file / virtual memory size?


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I don't know what is the cause, but it was concomitant with the instalation of the new firefox version, but it's more an assumption than a true fact

I'm not sure of what is a computer page file, after some research I've understand it's an other name for virtual memory size and not an other information (correct me if I'm wrong)

My virtual memory size is 25 600 Mo (automatically set by windows)


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Hi ptipersobonus, by default, Firefox only loads the "active" tab in each restored window. Is your Firefox set to restore all of the tabs at startup? That definitely would be a drag on performance. Or could any of your add-ons be taking actions that cause more tabs to be restored?

I don't know what system you use for backups, but I suggest saving a snapshot of your session history files now "just in case" something goes wrong with the automatic restore:

(1) To open your profile folder...

If Firefox is running:

You can open your current Firefox settings (AKA Firefox profile) folder using either

  • "3-bar" menu button > "?" Help > Troubleshooting Information
  • (menu bar) Help > Troubleshooting Information
  • type or paste about:support in the address bar and press Enter

In the first table on the page, find the Profile Folder row and click the "Open Folder" button.

If Firefox is closed:

Type or paste the following into the Windows Run dialog or the system search box and press Enter to launch Windows Explorer:


In that folder, do you see a semi-randomly-named folder? If so, click into it. If you find multiple such folders, find the one that was most recently updated.

(2) Copy out session history files

In your profile folder, double-click into the sessionstore-backups folder. Save all files here to a safe location such as your Documents folder.

(3) Typical files

The files you may find among your sessionstore files are:

  • recovery.jsonlz4: the windows and tabs in your currently live Firefox session (or, if Firefox crashed at the last shutdown and is still closed, your last session)
  • recovery.baklz4: a backup copy of recovery.jsonlz4
  • previous.jsonlz4: the windows and tabs in your last Firefox session
  • upgrade.jsonlz4-build_id: the windows and tabs in the Firefox session that was live at the time of your last update

Since these files are compressed, you need some tools to extract their contents, in the event that you need them for reference:


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