I-Firefox Community Forum

I am attempting to copy a FF profile from a Windows 11 machine I created it and am using it on to a brand new windows 11 machine on which I have also just installed FF on. Both machines are at FF 150.0.3. I have done a search online for the methods to do this but they have both failed for me.

The first one I tried was simply copying the profile from the existing (source) machine to the profile folder in the new machine however FF never recognized the copied profile on the new machine (I am using profile manager on both machines).

I then tried copying the profile using the method we used to use a while back to copy profiles which is to let profile manager create a new profile in the new machine, open FF so that it creates that new profile in the profiles folder then delete the contents of that profile leaving it as an empty profile (with the name of the newly created FF profile). Then, I selected and copied the *entire contents* of the source profile I was trying to copy and pasted them into the newly created profile I had just zero'ed out on the new machine so that the new profile now had the exact same contents as the source profile. I knew this copy was successful because it took a while to copy all of the data from the source profile to the new profile and the indicator showed it copying.

Again, FF did not recognize the new profile when I opened FF with the name of the new profile in the prof mgr.t.

Could someone tell me what I am doing wrong or what the problem may be? One problem I had when I first copied the source profile to my 32GB USB drive was a message saying "inbox folder is too big for destination system. " The source profile is 12.72 GB so there is plenty of room on the USB drive for it to fit. I have no idea why FF would have an inbox file so I just skipped it. The rest of the profile copied to completion once I did that but its size after copying was now only 7.65 GB, about 5 GB less than the original. Could this be my problem and if so, how do I fix it? Thanks for any help.

I read the existing articles and followed them, starting with "manage bookmarks". When I click on restore, there is a list of the last 15 backups by date. EVERY one of them results in an error message "unable to process the file".

Manually searching for bookmarks.html or json, resulted in nothing found at first. Then I discovered the path to the bookmarks folder were all hidden folders (after the 'user' folder). I got them to display in file explorer ('show hidden files' selected) and tried to manually select the JSON files that way, to restore bookmarks. That also did not work, resulting in the same message depicted below.

Please help

Latest Firefox release update wiped out my bookmarks. Tried to restore a saved HTML version - and it says "this file doesn't include any bookmark data". (This is a "Firefox HTML Document" property type, saved using the BACKUP feature on w/n Firefox itself - using "manage bookmarks".)

Dear Mozilla Support,

My name is Sizhe Xiong. Today when I launched Firefox on my Windows computer, the browser suddenly required me to select or create a new profile before continuing. I had no option to skip this step, so I created a new one.

After that, Firefox asked me to log in or register a Mozilla account. I used the same Gmail address that I’ve always used for Firefox Sync, but it seems that a new account was automatically created, and all my previous data — including bookmarks, history, saved passwords, and extensions — disappeared.

When I checked my local Profiles folder under C:\Users\<username>\AppData\Roaming\Mozilla\Firefox\Profiles, I found several new folders created around the same time, but none of them contain my old data (all places.sqlite files are around 5120 KB).

These bookmarks and passwords are very important to me. Could you please help check if it’s possible to recover my old Firefox data, or if my previous Sync data can still be linked to my Mozilla account (using the same Gmail address)?

Thank you very much for your help.

Best regards, Sizhe Xiong

Bookmarks in Firefox disappeared and cannot import my Bookmarks backup. I have tried to restore an older Bookmark file through /manage bookmarks/ import and backup/restore to no avail. thank you

Something very bad happened to me today (11/3)....

Firefox 144.0.2 was installed on 10/30/25, and everything has been fine until today. I don't know why or how, but ALL of my OPEN tabs (of which I have many--and have it fixed so they always re-open when Firefox starts), ALL went away.

In reading conventional steps to recover such from sessionstore-backups, those instructions sounded straightforward. However, even though ALL FIREFOX PROCESSES were ended, I could not copy the contents of the sessionstore-backups folder nor could I delete anything--EVEN THOUGH I am the owner.

Even after providing Admin perms.

I could get rid of profiles.ini, which initially proved diasterous, because then Firefox thought I was brand new, so ALL of my passwords saved through Firefox these many years, went "poof".

Fortunately, I was able to get that back, but I still cannot get all of my tabs back, and conventional instructions to do so aren't working.

After recovering from my heart attack for initially losing my passwords, I am breathing a little better right now, but it sure would be nice to get all of my open tabs back again. I don't know why I am not able to manipulate the files within sessionstore-backups. I think if I could eliminate the files in that folder EXCEPT for upgrade.jsonlz4-20251027123126, which possesses a 10/29/25 date, these should be the open tabs just before the 144.0.2 installation, and all should be right with the world, once more.

I have performed/examined many steps offered under this category, but most assume I can copy them elsewhere for safe-keeping and/or removing all but the one I want Firefox to "use". Because something is preventing me from doing this, though, I am being stymied in what ought to be the solution. As a test, I was able to copy files from a much older profile--so I can prove the basic steps SHOULD HAVE worked. Unfortunately, I cannot do the same with THE (more recent) folder in question. I can't get rid of parent.lock, either (and I have ensured no Firefox processes are running via Task Manager).

Repeatedly.

Something else is at work, here. Any help or assistance from community experts would be most helpful.

Thanks very much in advance.

-MG

My bookmarks have stopped working. When I went to Edit Bookmark I found they are all empty. I can create a new bookmark as usual, but I have over 300 bookmarks that no long function that are very important to my work. Is there any way I can possibly restore them, as my work depends on them?

I'm not sure whether i am in the correct forum. I have successfully copied to a USB stick the bookmarks from my old PC but, although I can open the html file and see them, I cannot see how to present them in the bookmarks menu. I am not recognising a simple "import" option such as I found with passwords. What am I missing

Hello,

This morning Firefox stopped loading new tabs, which usually means it is due for an update and restart. On my work computer, updates are managed by my organization, so I cannot prompt it to check for updates directly, but rather can just restart the application and it updates once closed. Today when I closed the window then clicked the shortcut to reopen, it notified me the exe file had been removed and prompted me to open the Windows store and reinstall, which I did. I have no indication as to why it uninstalled. All of my bookmarks and other history appear to have been wiped.

I have been trying on the support site to see if this data is recoverable, but nothing has panned out so far.

I have used Firefox as my primary browser for almost twenty years and frequently encourage friends and family to use it if they don't already. I have never experienced anything like this before. I am hopeful somebody will be able to assist me where reading through support center options hasn't yet, but if this is not resolvable, I'm done- the crash helpfully wiped everything clean, after all.

Any suggestions or response is greatly appreciated. Best, Z

I realize there have been several questions on this topic, even with the same subject heading.

The popup generally appears if you're trying to exit or refresh a page but haven't hit post or submit after entering data into a field. It's a good warning in case you've forgotten to do just that. I accidentally restarted Firefox after an update, and when I returned to the site I was working on I got this popup. Which makes sense, because I had entered in a ton of data and hadn't submitted it.

However, the page that I was returned to wasn't the one into which I'd entered my data - it was more of a home page for the website. I suspect this is a lost cause, but ... is it at all possible that the browser actually has that data saved somewhere and is waiting for me to complete submitting it? Or is this just a false positive?

Old laptop died , its not repairable, but the SSD Hard drive is OK , all the data on it and software is intact , but only thing I cant find or access is Firefox bookmarks and thats bad as i use them for my work ...what can i do to recover my bookmarks ???

I'm setting up a new computer, (Windows 11). Currently on a home WIFI network, in UTAH, with another computer, (windows 10). Very soon the new computer will be moving to my retirement home, in Nevada, on a new WIFI network.

Basically, How can I import Firefox bookmarks from another computer that is on the same WIFI network?

100% of my bookmarks have disappeared. I tried backing up to older version a month ago and still no bookmarks were found. I had over 2000 bookmarks. any suggestions?? Marty