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Firefox won't open local files in second filesystem

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  • آخرین پاسخ توسّط cor-el

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Firefox (113.0.1 (64-bit), Mozilla Firefox Snap for Ubuntu) won't open files in a filesystem other than the filesystem on which my home directory resides. I have a second filesystem mounted at /970 but trying to open any file whose URL starts with file:///970 elicits a "File not found" error message, e.g. "Firefox can’t find the file at /970/stuff.jpg". Setting security.sandbox.content.level to a lower number (I've tried 0, 1, and 2) does not fix the problem. I didn't have this problem with earlier versions of Firefox; it started after I upgraded to Ubuntu 22.04.2 LTS (x86_64)which got me a newer Firefox as well. Chrome continues to open files in /970 with no difficulty.

mount information for / (which includes my home directory) and /970: /dev/nvme0n1p2 on / type ext4 (rw,relatime,errors=remount-ro,stripe=32) /dev/nvme1n1p3 on /970 type ext4 (rw,nosuid,nodev,relatime,x-gvfs-show)

Firefox (113.0.1 (64-bit), Mozilla Firefox Snap for Ubuntu) won't open files in a filesystem other than the filesystem on which my home directory resides. I have a second filesystem mounted at /970 but trying to open any file whose URL starts with file:///970 elicits a "File not found" error message, e.g. "Firefox can’t find the file at /970/stuff.jpg". Setting security.sandbox.content.level to a lower number (I've tried 0, 1, and 2) does not fix the problem. I didn't have this problem with earlier versions of Firefox; it started after I upgraded to Ubuntu 22.04.2 LTS (x86_64)which got me a newer Firefox as well. Chrome continues to open files in /970 with no difficulty. mount information for / (which includes my home directory) and /970: /dev/nvme0n1p2 on / type ext4 (rw,relatime,errors=remount-ro,stripe=32) /dev/nvme1n1p3 on /970 type ext4 (rw,nosuid,nodev,relatime,x-gvfs-show)

All Replies (4)

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Fixing this in Firefox

In Firefox, first you need to navigate to about:config in the Firefox browser, search for the privacy. file_unique_origin setting, and set it from true to false by double-clicking it. Voila, super easy!

REGARDS, WILL

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This is likely one of the restrictions of using the Snap Firefox version. This version only allows access to your home directory.

You can look at Firefox from the official Mozilla server if you currently use a version from the repositories of your Linux distribution to see if it behaves differently.

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privacy.file_unique_origin is not present in Firefox 113.0.1. I set security.fileuri.strict_origin_policy to false and that didn't fix the problem.

cor-el's suggestion worked (thanks!) although that gives me a browser with none of my bookmarks or cookies. I'd be grateful for any tips on how to move those over from the snap version.

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Snap has its profiles in a different path in your home directory: REGULAR: ~/.mozilla/firefox/ SNAP: ~/snap/firefox/common/.mozilla/firefox/


You can copy certain files with Firefox closed from another profile folder to the current profile folder to transfer your personal data. Note that best is to avoid restoring a full profile folder.


  • bookmarks and history: places.sqlite
  • favicons: favicons.sqlite
  • bookmark backups: compressed .jsonlz4 JSON backups in the bookmarkbackups folder
  • cookies.sqlite for the Cookies
  • formhistory.sqlite for saved autocomplete Form Data
  • logins.json (encrypted logins) and key4.db (decryption key and primary password) for logins saved in the Password Manager
  • cert9.db for certificates stored in the Certificate Manager
  • persdict.dat for words added to the spell checker dictionary
  • permissions.sqlite for Permissions and possibly content-prefs.sqlite for other website specific data (Site Preferences)
  • sessionstore.jsonlz4 for open tabs and pinned tabs (see also the sessionstore-backups folder)