Firefox bookmark JSON file will not import as HTML: choose the matching route

By ON Lab · Sources checked November 8, 2026

A Firefox JSON/JSONLZ4 bookmark backup and a bookmarks HTML file are different formats. Use an HTML export with an HTML import command. Use Firefox's Restore route for a Firefox JSON or JSONLZ4 backup, but read its replacement warning first: restoring can replace the current bookmarks. Renaming the suffix does not convert one format into the other.

The reader question behind this guide describes selecting an HTML import command but seeing a recent JSON backup. The useful first step is identifying the actual saved file and intended operation, rather than repeatedly choosing different folders in the same file picker. This is a current-documentation guide; we did not restore or import anyone's bookmarks.

Choose the outcome before choosing the file

Do not choose Restore merely because the HTML picker filters out the file you have. Import and Restore have different effects on existing bookmarks. Decide whether you want to preserve the current collection and add material, or intentionally replace it with a backup.

If you can still open the source Firefox

For an HTML transfer, Mozilla documents the desktop Library route:

1. Open Firefox's menu, choose Bookmarks, then Manage bookmarks.
2. In the Library window, open Import and Backup.
3. Choose Export Bookmarks to HTML…, not Backup.
4. Review the save location and full filename, then save the export.
5. Locate that exact file before opening an HTML import command in the destination.

A default name such as bookmarks.html is a useful cue, but the name alone is not a completeness check. Keep the file you just exported distinct from an older backup with a similar date. Note the source browser and a few folders that must be present after import.

For the Chrome side of a transfer, use the separate Chrome HTML import and export guide. It does not turn a Firefox JSON backup into HTML; the correct source export still matters.

If you only have a Firefox backup

Mozilla's restoration guide documents Import and Backup → Restore → Choose File… for a saved backup. It also states that restoration replaces the current bookmark set. Preserve any current bookmarks you need before choosing this route and read the complete confirmation before accepting it.

This article does not recommend a restore into a browser you actively use merely as an incidental conversion step. If replacement is not intended, stop and identify an appropriate recovery or transfer plan instead. The existence of a backup does not authorize losing bookmarks created since that backup.

Do not paste the backup into a random converter solely because a file picker hides it. The documented Firefox routes already distinguish the formats. This guide does not validate third-party converters, compressed-backup parsers or profile-copy techniques.

Verify more than a success notification

After an intended import or restore, inspect the actual bookmark collection. A useful comparison includes:

• One bookmark that was near the start of the source collection.
• A bookmark inside a nested folder.
• A recent bookmark that should be present in the selected export or backup.
• Folder names and representative target URLs.
• Any current bookmarks that were meant to remain.

Reopen the bookmark manager after the operation and check those examples again. An imported collection may not appear exactly where you expected on the toolbar. Inspect the collection before repeating the import, because another import can make it harder to distinguish the first result from duplicates.

This is a recommended review workflow, not an observed result from a personal browser profile. The operation's completed message does not establish that every folder, tag or browser-specific item transferred exactly as intended.

If the file still does not match the operation

Record the full filename, which Firefox menu command created it, and which command is now trying to read it. Preserve the original file while investigating. An HTML-only selection dialog and a JSON backup are evidence of a format mismatch, not evidence that the backup is empty.

The current Mozilla export guide describes HTML as the transfer format and JSON/JSONLZ4 as Firefox backup formats. Its restoration guide also mentions a file-type choice for manual backups. Inspect the actual saved file rather than deciding its format from the menu command alone. The historical reader's menu wording is not a reason to assume today's commands are interchangeable. Match the file, operation and intended effect on existing bookmarks before continuing.

Sources

• support.mozilla.org: source guidance
• support.mozilla.org: source guidance
• support.mozilla.org: source guidance