bobperry

@nukecad Just tried out your fix and it works for me. Excluded file and checked "session", cleaned. Restarted FF and restored previous session. Thanks for checking this out! Bob

I just had this problem and someone on the forum helped with this. Try unchecking Applications/Firefox/Session. (see attached)

I finally got the blasted thing working (I guess) this morning. I've looked in logs and prefs. I disabled all extensions in FF56.0 and only enabled Xmarks. I even opened Tools/Options/Privacy&Security and clicked "Saved Logins" to see if there was anything in there (there wasn't). Cleaned and re-started. There is a large (32 character) alpha-numeric cookie that I "kept" and now, after much travail, seems to sync my bookmarks. So I guess it was the weird "cookie" and not a FF profile issue. I'm not really sure at this point. Will cross fingers. Lastpass / Xmarks used to be a good company, but now seems flaky and unconcerned about communicating with it's users. I know that there will be a lot of confusion in the next several versions of FF and I can't wait until things stabilize in Jan/Feb. Thank you all for your help! I consider this issue solved and really a Xmarks code problem.

.@Nergal - No it has not fixed this issue. I looked for a cookie that I might save, but did seem to find one. I will keep trying different things but would appreciate any help. Bob

.@Andavari - yes. I edited post to reflect correction. Thanks!

Thanks @Nergal, that seems to have worked!

Win 10 (64bit) CCleaner 5.35.6210 (64bit) Updated (FF Extension) to Xmarks Bookmark Sync 4.5.0.1a (development version) in Firefox 56.0 (64bit) to be compliant with new FF release. After cleaning with CC it requires me to re-enter login info even though "remember me" is checked. Is there a file that I can exclude to prevent this? Thanks! Bob

Win 10 (64bit) CCleaner 5.35.6210 (64bit) I installed FF 56.0 (64bit) last night on 2 different computers and made sure options were all correct. FF: Tools / Options / General, When FF Starts: Show your home page (which is start.DuckDuckGo) I browsed today and closed FF. Opened CC and Run Cleaner. CC Firefox checked: Internet cache Internet History Cookies Download History Last downloaded Location Session When I opened FF it did not open to start page, instead it tried to open my previous tabs. I re-checked FF options and all were set correctly. I re-browsed to some sites in several tabs and closed FF and again ran CCleaner. Same results - tried to open old tabs. I repeated the process again, closed FF and did NOT run CC. Opened FF and it started correctly. Conclusion: CC is deleting a new file in this version of FF 56.0 and I do not know what it is or how to troubleshoot. thanks for any help! Bob