Can You Recover Deleted Firefox sessionstore Files

Yvette Bonnet updated Jul 08, 26

5 min(s)

Deleted Firefox sessionstore files can sometimes be recovered if the original sessionstore.jsonlz4 or related backup files were removed recently and have not been overwritten. Firefox session file recovery is most practical when recovery starts early, Firefox is fully closed, and the profile folder still contains usable backup session data.

Step 1
Close Firefox completely before any recovery attempt. Use Task Manager, Activity Monitor, or another system process tool to confirm Firefox is not still writing to the profile folder.
Step 2
Check the Firefox profile folder for existing session backups. Look for sessionstore.jsonlz4, previous.jsonlz4, recovery.jsonlz4, recovery.baklz4, and files inside the sessionstore-backups folder.
Step 3
Restore from local backups first. If File History, Time Machine, cloud version history, or another backup tool is available, recover the deleted session file from the original Firefox profile location.
Step 4
If no backup exists, scan the drive where the Firefox profile was stored. Save recovered files to a different drive and look for JSONLZ4 session files, profile-folder remnants, or older session backups.
Step 5
Replace or test the recovered browser session file only after copying the current Firefox profile. If Firefox starts without restoring tabs, test another recovered session backup from the same profile.

Common Issues and Fixes

Session file is found but tabs do not restore: likely cause is corruption, incomplete recovery, or wrong profile placement; fix by trying previous.jsonlz4, recovery.baklz4, or another file from sessionstore-backups.
No session files appear in recovery results: likely cause is overwritten data, SSD TRIM, or scanning the wrong profile drive; fix by stopping source drive use and checking older system backups.
Recovered file has the wrong date: likely cause is Firefox creating a newer blank session after a crash or restart; fix by comparing timestamps across all recovered profile and session files.
Firefox profile folder is missing: likely cause is profile deletion, profile reset, or browser refresh; fix by recovering the full profile folder instead of only one session file.
Recovered file opens as unreadable text: likely cause is JSONLZ4 compression; fix by keeping a backup copy and testing the file through Firefox or a proper JSONLZ4 viewer instead of editing it directly.

Quick Tips

sessionstore.jsonlz4 often works together with other profile data, so recovering the whole Firefox profile can be more useful than recovering one file alone.
SSDs with TRIM enabled may remove deleted browser session file data quickly, which can limit Firefox session file recovery.
Sync services may replace local session files with newer empty versions, so version history should be checked before local recovery attempts.
Private browsing windows usually do not restore as normal session data, even if a browser session file is recovered.
Always work on profile copies when testing recovered files so Firefox does not overwrite the only remaining session backup.

💡Protip:

Recover the full Firefox profile folder when possible, not only sessionstore.jsonlz4. Profile-level recovery gives you more session backup candidates and helps avoid losing context from extensions, profile IDs, and related browser data.