How To Recover Bookmarks
There are 2 ways of completing this task, depending on whether you have just deleted the bookmark or if Firefox was closed since.
In Firefox, click "Bookmarks", then "Show All Bookmarks". In the menu that opened, click "Organise" then "Undo". This should have restored the bookmark. If it did not then try method 2.
Before you attempt this, be aware that it will replace all your current bookmarks with the ones that existed at the time of the auto-backup.
In Firefox, click "Bookmarks", then "Show All Bookmarks". In the menu that opened, click "Import and Backup", then "Restore". This will show a list of backups to your bookmarks that Firefox automatically made. By selecting one of these will replace your current bookmarks with the ones in the backup. Select the one that last had the lost bookmark in and then click "Ok" to the confirmation.
After this is done it would be a good idea to make your own backup. To do this in Firefox, click "Bookmarks", then "Show All Bookmarks". In the menu that opened, click "Import and Backup", then "Export Bookmarks to HTML". This will then save a HTML file containing all your bookmarks. To restore them, follow the same instructions but click "Import Bookmarks from HTML" then select your backup file.
Do not open or close the chrome browser. Chrome only makes 1 backup by its self and when you open Chrome it overwrites the backup file with the current bookmarks. It is recommended to try the recovery, then after make your own backup.
If you have just deleted the bookmark a few seconds ago and have not closed the browser, go to "chrome://bookmarks" and right click an empty space in the bookmarks area, if there is an active option to undo, this may restore your bookmark. Otherwise follow the further instructions. As mentioned above, do not open or close Chrome.
Open Windows Explorer and do to the following directory, where "USERNAME" is the logged on user:
At this point close Chrome. Then delete the file "Bookmarks" and rename the "Bookmarks.bak" to "Bookmarks". The .bak file is the auto-backup made by Chrome.
The .bak extension may be hidden, you may need to change the view setting “Hide extensions for known file types” in Windows Explorer.
Open Chrome and put "chrome://bookmarks" into the URL bar and press enter. This will open the bookmarks page for Chrome. Click "Organise" then "Export Bookmarks to HTML file" to make your own backup file.
To restore these, follow the same instructions but click "Import Bookmarks from HTML file".