Not starting second time
On windows 7 64bit firefox always starts fine first time after machine switch-on but recently (~ last 6 months since v65) restarting firefox a second time often (not always) causes nothing to appear on screen but task manager shows that it is running in the background. Today I tried restarting firefox in safe mode (after it exhibited the above behaviour and shutting it down in task manager) and it restarted fine. I then tried restarting firefox in normal mode and it again started ok. I've tried refreshing and reinstalling firefox, turned about:config/browser/tabs.remote.autostart to false but this is still happening intermittently. AdBlockPlus is the only extension installed, shockwave flash the only plugin.
ప్రత్యుత్తరాలన్నీ (2)
Do you still have the issue if you manually disable AdBlockPlus?
Usually, when an issue doesn't occur in Safe Mode, it's a clear indicator that the problem is caused by an installed extension.
The only other causes of the issue that I can think of would be a theme you have installed on Firefox or hardware acceleration, both of which are disabled in Safe Mode.
Hope this helps.
I've disabled AdBlock Plus and so far so good. Hardware acceleration and multiprocessing are turned off and the theme 'Mountain Belledonne France' seems ok. I'll report back if the problem persists. Thanks for your help...