Sorry to hear about this problem. Is the backup file one of the ones that Firefox creates automatically, or one you made "just in case" before your uninstall?

If it's one that you made, try changing the file extension from .jsonlz4 to .json since the manual backup does not use lz4 compression.

If it's an automatic backup, could you "drop" it on this tool and see whether you can create an HTML-format export file from it?

https://www.jeffersonscher.com/res/bookbackreader.html

To import an HTML-format export file, see: Import Bookmarks from an HTML file.

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

• use "Verify Integrity" on the "Help -> Troubleshooting Information" (about:support) page

See also:

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

THank you very munch. The convert to Json doesn't wort but in HTML is ok.

I lost my "Tags" but i recover all my bookmarks.

Thanks again for you help

Sorry about the tags; there's no place to put them in the HTML format.

I've used the above site for similarly broken backups from February 2010, https://www.jeffersonscher.com/res/bookbackreader.html and gotten an "unexpected token ]" at a character position. Turns out in old Mozilla backups, the last comma before the closing square and curly bracket in the JSON file breaks the entire file. How silly that is! Stil, removing that comma fixes the issue, so there you have something you can investigate and try.