When Firefox works with SQLite databases like cookies.sqlite, it creates temporary or "journaling" files like cookies.sqlite-wal and cookies.sqlite-shm. When you exit Firefox, it should reconcile and remove the two temporary files.

If the files aren't being removed, Firefox may be encountering some problem working with cookies.sqlite and the temporary files, like a file permissions problem or a file lock. (Your guess is as good as mine at this point.)

If the temporary files are still there after Firefox closes, allowing 15 seconds to finish file updates, you can delete them and see what happens going forward.

Just in case you or anyone reading wants a step-by-step for that:

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, on the Profile Folder row, click the "Open Folder" button. This should launch a new window listing various files and folders in Windows Explorer.

Leaving that window open, switch back to Firefox and Exit, either:

• "3-bar" menu button > Exit
• (menu bar) File > Exit

Pause while Firefox finishes its cleanup, find and delete these files:

• cookies.sqlite-shm
• cookies.sqlite-wal

When you run Firefox, it will create new versions of these files, hopefully with more reasonable file sizes.

thanks but is it safe if i delete them .?

By "safe", do you mean, is there a chance that you will lose some existing cookies? It's possible; that could log you out of some sites you're currently logged into. Websites will set those cookies again the next time you visit.

thank you very much i did it and it work