This must be a new (bug?) with either Firefox 55.0.2 or CCleaner 5.33.6162, because I used to always clean "Internet History" with no problems like this, but now when I do so, opening Firefox all my Favicon's are gone from my bookmarks. I've narrowed it down to CCleaner's "Internet History" option that does so.
Please check the following thread: https://forum.piriform.com/index.php?showtopic=48688&p=285717
That's exactly that! Glad to know it's not just me, Hope it gets addressed in the next release anyway that thread title sucks.
Still not fixed in v5.34.6207 despite the claim in the changelog. : /
Still not fixed in v5.34.6207 despite the claim in the changelog. : /
Same here !