You can extend the hangmonitor wait timeout and create a new Number pref on the about:config page and increase the value from its default of 10000 milliseconds.

• about:config => browser.hangNotification.waitPeriod

You can open the about:config page via the location/address bar. On the warning page, click "Accept the Risk and Continue" to open about:config.

• https://support.mozilla.org/en-US/kb/about-config-editor-firefox

testing ...

cor-el:

Couldn't find that key however:

dom.ipc.processHangMonitor=false

... seems to have worked. Tx.

Please mark as resolved if you have no more questions and have a nice day.

I'd not consider it really resolved until I hear back. Cor-el's key didn't exist, and I'd like to hear from him what he has to say about that. My suggestion *seems* to work, but is it really the proper answer? I don't know.

I wrote above create a new Number pref on the about:config page as this is an example of a pref that is hidden by default (a default value of 10000 is assumed) and needs to be created if you want to adjust its value. Increasing the hang timeout instead of disabling this feature allows to recover from cases where it takes very long or Firefox hangs and you may have to kill the browser to regain control.

Ah! I was unclear about that, I resolved it in my mind as a modification of what must obviously exist (so as to be modifiable) so ignored 'create' -- which I didn't know you could do, anyway. Program settings are usually something you can indeed modify, but not invent. (IMHO hiding options is a very bad idea but that's just me.)

Implemented! And even without testing, I'll consider it done. Tx.