Hi xignt, It is quite possible that you are being affected by having clear history on shutdown checked.

• [Bug 1005958 - Disable seer until new backend is rewritten ]
• [Bug 965309 - Worker hang at shutdown with XHR]

This will be alleviated as they work on a patch for this issue. However they are looking for a regression window on this issue and you can check it out in the second bug. What is the options selected for history? 'remember history'?

Looks like at present ^#c14 they are not too interested in a specific regression range.

Does Firefox work ok if you do not set Firefox to clear History on closedown ?
If so it probably is an effect of the above mentioned known bugs.

I imagine Firefox will still be able to run a Private Browsing Window without problems, but you may need to close that before exiting from Firefox.

(One of several related threads is firefox already running when trying to open Firefox /questions/1001267#answer-577670 )

https://support.mozilla.org/questions/997866?esab=a&s=&r=1&as=s
This is not a cure but will make it easier if Firefox locks up.

Thank you, I did have my history set to not remember browsing history, and to clear cache and browsing/download history on exit. After temporarily re-enabling those history items, exiting, restarting and visiting a web site, exiting again, and re-disabling those history items, further startups/exits worked fine without leaving a process running. So that seems to be the work-around "fix" until the underlying bug(s) are addressed.

Glad to hear that helps.

It appears this or related bugs affected other versions also, but depends partly on the Firefox configuration. The main factor being the clearing of History when Firefox closes down.

I guess that most users do not set Firefox to clear History, after all it takes away the the handy feature of the location bar being able to predict addresses based on History & the ability to look at your history. It is something I would have hoped Telemetry would have picked up and so alerted engineers, but maybe those users clearing History are not enabling telemetry.

• Share data with Mozilla to help improve Firefox

That feature was IIRC introduced after developers missed a Firefox 4 memory usage issue.

Learned a couple more things:

1. The first fix didn't stick after the next power cycle. Still have the problem while history items are disabled.

2. Telemetry actually appears to be part of the issue. Even with history automatically cleared/disabled, enabling telemetry by itself clears the problem, and disabling it brings the problem back.

Go figure. Hope this is helping someone with their detective work....

Hi xignt,
Thanks for the update.

Sounds like a good reason to turn on telemetry.

;-)

Mixed and unexpected results then. This problem has proved rather difficult to reproduce reliably and only affects some people. Problems that affect everyone or are easy to demonstrate and reproduce tend to be easier to investigate and fix.

I am no expert on the closedown problems. One of the bugs does mention the process is rather fragile. Presumably problems may be affected by many things that are involved with the close down procedure.

I guess you have demonstrated that telemetry is one of those processes. Interestingly if telemetry use actually helps and prevents the hang that may be distorting the view of developers when looking at the telemetry results. I wonder if this could make the problem appear less severe.

If I understand correctly you are now reporting that

1. Setting Firefox to remember History does help whilst the computer is powered up and Firefox is closed and reopened repeatedly with success.
2. Once Firefox is closed down and then the System closed down and powered off the problem reappears.

• Have you looked at the settings ?
  Does the preferences display indicate the setting has changed after powering on.
  Is Firefox again then set to something other than Remember History.

I suspect we will need to wait for the fixes to the known bugs to work there way through before doing any serious troubleshooting on this issue.

Thanks for the response, and you are right, for now the only one being helped by leaving telemetry on is me, because there is (apparently) no problem to report when it is on.

Slight clarification:

1. Enabling history and cache fixes problem.

2. Enabling telemetry fixes problem.

3. Enabling history and cache, cycling FireFox on/off, then disabling history and cache, fixes problem during current power cycle, but not persistently between power cycles.

4. All the above settings do persist across power cycles.

Thanks for the clarification.

Telemetry report startup and other performance related data it is always useful to developers to have telemetry enabled. Note aggregated annonymised results are available

• see the interactive results at http://telemetry.mozilla.org
• Your own results stored on & from your own computer
  • If FHR is on, & has been running a while. (Still rather limited it is Work In Progress) about:healthreport
    see Firefox Health Report - understand your browser performance
  • Again assuming it is enabled and has been for a while about:telemetry
    The first one
    Slow SQL Statements
    could be of interest,
    and with problems on the original Fx29.0 may well have picked up issues with netpredictions.sqlite whilst that was enabled

UPDATE

Note one potential fix is now in the very recent Firefox Beta 30b8 Initial reports suggest this fixes the issue. ^{(Bug1005487#c38)} If you have been suffering from this problem and want a fix now instead of in a few weeks time you may wish to download and install the Beta version of Firefox.

The beta version is effectively a release candidate but is only intended for advanced users or testers. I would be interested to hear feedback from those of you that do test this out.

Beta version download

• http://www.mozilla.org/en-US/firefox/channel/#beta/beta-desktop