How to diagnose random freezes


A thunderbird 60.9.0 on Debian GNU/Linux stretch freezes during a few seconds (sometime one second and up to ten seconds). When frozen the characters entered while writing a mail are ignored and the menus are unresponsive. When the freeze is over, things resume normally. After a few days of observation nothing stands out as the root cause: it seems to be random, occurring as frequently as a few times per hour and sometimes only once every two hours.

Instead of trying to guess what could cause these freeze, I’d like to know how to properly diagnose them. I tried looking at the error console but nothing shows before or after the freeze.

Does anyone have a recommendation ?

P.S. I’m quite sure the freeze does not originate from a process unrelated to thunderbird overloading the machine etc. because other software such as Firefox do not exhibit the same problem.

I’m sorry to report that this is a horribe conclusion based on flawed logic.

Anyway, the first, highly revealing diagnostic you can do is the following (response revised because you are debian and not Windows):

Start debian.

Start thunderbird in safe mode

Does problem go away?

  • If no, then cause is either: bug in Thunderbird, something in your Thunderbird profile, your mail provider (eg a setting, file or folder), cannot rule out something in your environment

  • If yes, then start Thunderbird normally
    – If problem came back, then cause is likely a Thunderbird addon - eliminate addons by disabling half at a time in Tools | addons | extensions and restarting
    – If problem is still gone it could be Thunderbird cache related that got cleared by Thunderbird safe mode

  • If results are unclear … possibilities include temporary conditions such as contention from other running programs, background tasks such downloads related to updates, failing disk hardware, …

Please let us know your findings.

Thanks for the quick reply. Shortly after posting I realized the version of thunderbird (60.9.0) was missing and the operating system as well (Debian GNU/Linux stretch) and updated the post accordingly.

We will try to repeat the problem in safe mode, thanks for suggesting this!

The freeze problem (which happens at least once per hour and often more frequently) does not show in safe mode (1 day experiment). It does not show either when all addons are disabled (about 3 hours experiment). This strongly suggests an addon is the cause and we will re-activate each addon, one after the other, to find which one is responsible.

It is a tedious process but it will narrow down the source of the freeze to one or more addons. I will update this issue when there is more information.

Great to hear you are making progress, and look forward to your final results.