Look on your desktop. Do you see a folder called; Old Firefox?

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

https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

https://support.mozilla.org/en-US/kb/how-run-firefox-when-profile-missing-inaccessible

You can check for problems with the places.sqlite database (bookmarks and history) in the Firefox profile folder.

• https://addons.mozilla.org/firefox/addon/places-maintenance/

See also:

• http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox
• https://support.mozilla.org/en-US/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file

If the Places Maintenance extension can't repair the places.sqlite database then remove all places.sqlite file(s) in the Firefox profile folder to make Firefox rebuild the places.sqlite database from the most recent JSON backup in the bookmarkbackups folder.

• keep a backup copy of places.sqlite in case a new places.sqlite database has to be created
• http://kb.mozillazine.org/Unable_to_process_the_backup_file_-_Firefox

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

The bookmark count of 16 may be a little misleading. In a test profile, I restored a bookmark backup with an indication of 15 bookmarks. It contained:

Bookmarks Toolbar:

• Most Visited (smart folder)
• Getting Started (standard bookmark that comes with Firefox)

Bookmarks Menu:

• Recent Tags (smart folder)
• There is a separator here
• Mozilla Firefox folder
  • Help and Tutorials (standard bookmark)
  • Customize Firefox (standard bookmark)
  • Get Involved (standard bookmark)
  • About Us (standard bookmark)

Other Bookmarks:

• 1 bookmark I created

Adding up every single one of those lines yields 13 things. The root bookmarks folder may be a 14th thing. I don't know what the 15th thing is. But if this is similar to what you got when you restored the file, you probably will need to discover a much larger file somewhere else on your system.

The count includes separators and folders (i.e. is a total item count) and is not about just bookmarks.