User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:46.0) Gecko/20100101 Firefox/46.0 Build ID: 20160411042519 Steps to reproduce: OS: (old) Win10 stable via update from Win8.1 (new) Win10 build 14295 fresh install Here's few thing I done when I reinstall my Windows: on the old system, the problem that Firefox's jumplist not showing up is already there. (on old system) go to "%AppData%\Mozilla" and copy my whole profile as backup. (on new system) after installed Firefox, unchecked "Start Firefox now", then copy back my old profile and start Firefox. this would cause jumplist broken. I tried again, but this time tried exclude any file related to session and jumplist. it works, but after I set up Firefox Sync and after syncing, the jumplist is broken again. TL;DR: directly "clone" my profile or sync my Firefox would lead to broke my jumplist. Actual results: the jumplist is broken (only appear Firefox title, pin/unpin to the taskbar and close all windows). Expected results: the jumplist should behaves normal. (especially after sync)
Check prefs browser.taskbar.lists.* in about:config.
here's all browser.taskbar.* parameters as they're all default: browser.taskbar.lists.enabled; true browser.taskbar.lists.frequent.enabled; true browser.taskbar.lists.maxListItemCount; 7 browser.taskbar.lists.recent.enabled; false browser.taskbar.lists.refreshInSeconds; 120 browser.taskbar.lists.tasks.enabled; true browser.taskbar.previews.cachetime; 5 browser.taskbar.previews.enable; false browser.taskbar.previews.max; 20
Any relevant errors in Browser Console? https://developer.mozilla.org/en-US/docs/Tools/Browser_Console
I'm putting a startup log here: pastebin - http://pastebin.com/vzhW6G8w
I'm not sure what involvement Sync could have here; Sync doesn't really sync any relevant prefs. Does this still happen?
Shell Integration doesn't have any code for the taskbar or jumplists. Moving to sync in the hope that is the correct component.
Sync knows nothing about jumplists. I see mentions in widget/windows, so let's try there.