Wrong Favicons in Firefox

Question

I am getting wrong favicons when I bookmark sites in Firefox 56.0 (64-bit).

For example, when I bookmark Stackoverflow.com, I get a favicon for Reddit.com.

Any idea why this would be, or how I can fix it?

Note: This is the only site this is currently occurring with, but it happens every time when I remove/re-add the bookmark.

Stack Overflow Showing Reddit favicon:

Correct favicon Shown in Media Tab:

Edit 11/25/17

Happening now on Drudge.

The accepted answer below does fix it.

Answer 1

Close firefox, delete %AppData%\Mozilla\Firefox\Profiles\<your profile>\favicons.sqlite

This is easier to do than peqhusus's solution, but it does mean you'll lose all cached favicons and have to reload your bookmarks to get the icons again.

Answer 2

This may not be the best solution if you are only slightly annoyed...

What I usually do when this happens is go to

Bookmarks --> Show All Bookmarks --> Import and Backup --> Export Bookmarks to HTML file

Then open the bookmarks file, find the corresponding bookmark entry, then change ICON_URI="{URL}" ICON="data:image/png;base64,{data}

to the URL of the icon and the base 64 encoded icon in png format

Then import the modified bookmarks file back into Firefox

Answer 3

Clearing the web cache should force Firefox to download the favicons again.

1. Close all the tabs except a new one
2. Go to Tools > Options
3. Click the Advanced on the left panel, then the Network tab
4. Find Cached Web Content and click the Clear Now to the right
5. Restart Firefox