Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

I have many tabs and instead of opening upon click, they open all at once which makes FF freeze.

more options

Hi,

I currently have 160 tabs open, but every time I opened Firefox, they didn't load until I clicked on them. That made it possible to quickly go onto Facebook or other sites quickly by opening a new tab, and then close the browser and get back to it later. Recently they crashed and I restored them, but after that, every time I open Firefox, all 160 start loading all at once (might not be tabs from previous session, but tabs set as homepages), and you can imagine how much memory it takes. I still have the "restore tabs from previous session" option chosen.

What's the problem? I can't directly contact mozilla, which is very frustrating in this situation, since FF is my main browser and I'd like to solve the issue quickly - I'd be grateful for suggestions and ways of fixing it. I'm not looking to be informed that having as many tabs open at once isn't a good idea - that's just how many I need at the moment, but it's impossible to use Firefox if they all start loading.

Hi, I currently have 160 tabs open, but every time I opened Firefox, they didn't load until I clicked on them. That made it possible to quickly go onto Facebook or other sites quickly by opening a new tab, and then close the browser and get back to it later. Recently they crashed and I restored them, but after that, every time I open Firefox, all 160 start loading all at once (might not be tabs from previous session, but tabs set as homepages), and you can imagine how much memory it takes. I still have the "restore tabs from previous session" option chosen. What's the problem? I can't directly contact mozilla, which is very frustrating in this situation, since FF is my main browser and I'd like to solve the issue quickly - I'd be grateful for suggestions and ways of fixing it. I'm not looking to be informed that having as many tabs open at once isn't a good idea - that's just how many I need at the moment, but it's impossible to use Firefox if they all start loading.

All Replies (1)

more options

Let's try something: the preference that controls whether ALL tabs load when you restore a previous session, or only the active tab in each window, is called:

browser.sessionstore.restore_on_demand

Normally, this is set to true, but if it is set to false, then all tabs will load, severely bogging down Firefox's startup.

Since you can't very well start Firefox up and fix this using about:config, we're going to have to check a couple settings files in your currently active profile folder. Roll up your sleeves, get some coffee, here we go.

(1) Locate your active profile folder

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

%APPDATA%\Mozilla\Firefox\Profiles

This should display one or more folders. If there's only one, go ahead and click into it. If there's more than one, find the one with the most recently updated contents.

(2) Check preferences files

The main preferences file is prefs.js -- if Windows doesn't display the .js extension, you can switch that setting. See: https://www.tenforums.com/tutorials/62842-hide-show-file-name-extensions-windows-10-a.html

Don't double-click .js files! That will execute them as system scripts, which can be very bad news. This file doesn't change anything in Windows, but as a general practice...

You can open prefs.js in Notepad (or your favorite text editor) by right-clicking and choosing either Edit or Open With. Then look for this line:

pref("browser.sessionstore.restore_on_demand", false);

If you find that, delete the entire line. Then save and exit the file. If you use a word processor for this, make sure it saves in plain text format. Any weird formatting characters will probably corrupt the file and wipe your custom settings.

Check for an optional settings file named user.js in the same profile folder. If you find it, check for the same setting, etc.

(3) Start Firefox again

If all is well, you'll be back to the normal "restore on demand" setting.

If Firefox fails to restore your session: this could indicate that prefs.js got corrupted. For now, go to the History menu and select Restore Previous Session. Then go back to the Options page to make sure your Startup setting is correct.