You can get more details by visiting about:processes in the address bar (Shift+Esc).

Thanks, here it just shows me on the first level that Firefox (21480) uses a lot of GB, but neither the tabs nor the utilities or extensions are noticeable.

Do you have a lot of Firefox windows open?

Does it still happen in Troubleshoot Mode?

How much free space is there on the hard drive since I see these values in the System Details ?

memorySizeBytes: 34359738368
diskAvailableBytes: 56058642432

If you have submitted crash reports, please post the IDs of one or more recent crash reports that start with "bp-".

• bp-xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

You can find the report ID of recent crash reports on the "Help -> More Troubleshooting Information" (about:support) page.

• click the "All crash Reports" button on this page to open the about:crashes page and see all crash reports.

Alternately, you can open about:crashes via the location/address bar.

See "Viewing reports outside of Firefox":

• https://support.mozilla.org/en-US/kb/mozillacrashreporter

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-crashes-closing-or-quitting
• https://support.mozilla.org/en-US/kb/firefox-crashes-asking-support

@zeronight: no i don't and yes it still happens in troubleshoot mode

@cor-el

Many thanks for your inputs.

There are still 73 GB left on the hard drive.

Here you go with some recent crash report numbers: bp-c226ddbd-8ea2-4705-9a27-445ea0240312 bp-01eda940-4c25-480a-a503-29b160240312

Thank you for your help!

Does it still happen in a new profile? An easy way to test a new profile is to install Developer Edition and see if it happens there or refresh your existing profile. Make sure you stay signed out of your sync account when testing.

@zeroknight Many thanks! It does not happen in Developer Edition.

Could be a problem with storage or the quota manager.

You can check for issues with Storage (indexedDB).

• https://firefox-storage-test.glitch.me/

You can create a new profile as a quick test to see if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

If the new profile works, you can transfer files from a previously used profile to the new profile, but be careful not to copy corrupted files to avoid carrying over problems.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile