STR: 1. open Firefox Nightly 2. Wait for all tabs to show up 3. Click on a random tab Actual result: URL shows up but no content Expected result: URL shows up and content starts loading Note: pressing enter/reloading works in most case, unless the tab has a #anchor Application Basics ------------------ Name: Firefox Version: 54.0a1 Build ID: 20170204110423 Update Channel: nightly User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:54.0) Gecko/20100101 Firefox/54.0 OS: Linux 4.4.0-59-generic Multiprocess Windows: 4/4 (Enabled by default) Safe Mode: false

I can reproduce that with some of my pinned tabs as well although not systematically

I am seeing the problem just now in Firefox53.0a2. When the problem occurred, Browser console shows the following error. NS_ERROR_FAILURE: Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsISerializationHelper.nsISerializationHelper] 1 Utils.jsm:135 The restored tab is empty, F5 does nothing. The tabs of restored are completely broken. Page can be loaded in new tab. Reproducible: none

Seems regressed by Bug 1307736. And maybe duplication of Bug 1334875

FF54 was fixed in bug 1334875. Mark 54 fixed.