Please have a look at the Mozilla Crash Reporter article, in particular the section about viewing reports outside of Firefox, to see if any reports are available.

The "Error during ... init" errors may be a known issue that could do no harm, but I can’t tell whether or not they are related to your current issue.

Does the site crash start when you open it in a new profile?

Thanks - great to have a quick reply! Answers:

" Mozilla Crash Reporter" - I did go there, but could not find any relevant crash reports on my system

"...viewing reports outside Firefox" - ~/.mozilla/firefox/Crash Reports/submitted reports as 'Empty'.

~/.mozilla/firefox/Crash Reports/ contains 34 items such as "InstallTime20170612122526 10bytes" - searching on these yields no results.

I followed the "New Profile" link and created 'Jn17crashtest'. Booting it from Terminal it opens ok but on asking it to 'Refresh' it crashes with the same dialogue "Firefox had a problem and crashed. Unfortunately the Crash Reporter is unable to submit a crash report. Details: the application did not leave a crash dump file"

Although I can still use Firefox for everything else [so far] it is very annoying to get these crashes on that website & not to be able to 'refresh'. Further advice would be very welcome.

Nicc said

I followed the "New Profile" link and created 'Jn17crashtest'. Booting it from Terminal it opens ok but on asking it to 'Refresh' it crashes with the same dialogue ..."

Interesting, but slightly confusing. ;) Did you refer to refreshing/reloading the particular website that does get loaded in the new profile but makes Firefox crash when reloading it, or to starting the Refresh Firefox feature afterwards? In other words: if (you forget about the Refresh feature but) only create and launch a new profile, what happens when loading the website for the first time?

^{Note that the Refresh feature is only needed in rare circumstances when an issue comes up and to fix a corrupt profile, not periodically or after each Firefox crash. Basically it creates a fresh profile and only adds back the most important files (that should not be able to cause a crash), as outlined in the Refresh article. Nevertheless, Firefox should not crash in the new profile that I assume you launched properly after creating it (you should see the default startup page, no bookmarks etc.) Performing a Firefox Refresh for a new profile would be to no avail for logical reasons. If you did so for your regular profile, note that a previous session can be restored so it might help to do this in a new session, or at least without having that particular website opened, but testing in a fresh profile is more valuable.}

If the website still crashes in a new profile, could you name it here so we can see what happens when loading it? Additionally, your issue may be too Linux specific for me right now so hopefully someone else can help out. Since there are a number of other support questions with regard to Firefox crashing on Linux, I feel there must be some bug involved. (If you use Flash, this bug may be a lead or related.) Checking for updated packages as well as the system requirements may help. Could you also report your Linux/Ubuntu version?

OK, many thanks again. Lots and lots of Questions here. Dealing with them one by one: "...Did you refer to refreshing/reloading the particular website that does get loaded in the new profile but makes Firefox crash when reloading it,"

No, the site in question is the Santander banking site which forced me to take the deeply unwanted Adobe flash some time ago. The problems with Santander are recent and intermittent: it will usually allow me to log on then crashes Firefox [with that message]. If I restart Firefox I can continue for a while before it crashes again, and again, and again, but I can complete tasks eventually and log out - all is then calm. The reason I've couched this query around 'Refresh' and 'Safe Mode' within Firefox is that invoking them instantly crashes Firefox [with that message] every time and that [to my simple mind?!] would seem to be at the core of the problem[?].

"or to starting the Refresh Firefox feature afterwards?" Yes - that crashes Firefox [with that message].

"In other words: if (you forget about the Refresh feature but) only create and launch a new profile, what happens when loading the website for the first time?" I'm reluctant to do that bearing in mind security issues and possible moans from the bank's profile monitoring, but if we get nowhere after this I'll take the risk.

".... Nevertheless, Firefox should not crash in the new profile that I assume you launched properly after creating it (you should see the default startup page, no bookmarks etc.)"

OK, just to check I didn't cock it up I've doe it again thus: 1/ Firefox is closed [crashed on 'Restart in Safe Mode'] 2/ In Terminal ran: firefox -P OUTPUT: (firefox:2843): GLib-GObject-CRITICAL **: g_object_ref: assertion 'object->ref_count > 0' failed (firefox:2843): GLib-GObject-CRITICAL **: g_object_unref: assertion 'object->ref_count > 0' failed (firefox:2843): GLib-GObject-CRITICAL **: g_object_ref: assertion 'object->ref_count > 0' failed (firefox:2843): GLib-GObject-CRITICAL **: g_object_unref: assertion 'object->ref_count > 0' failed

BUT also The Firefox Profile Manager opens. In the Profile Manager I Create 'Jn17crashtest2' and invoke it- there are no favourites, history etc. I go to the Santander website [but don't log on] - all behaves as it should for 13 seconds then it crashes Firefox [with that message]. I close The Santander website. I go to Menu>?>'troubleshooting Information'>'Try Safe Mode'>Restart. That instantly crashes Firefox [with that message].

" Performing a Firefox Refresh for a new profile would be to no avail for logical reasons." Fully understood, but surely 'Refresh' or 'Try Safe Mode' should not crash a new profile? [even if, as agreed, it's pointless!]

"If the website still crashes in a new profile, could you name it here so we can see what happens when loading it?" I don't think the website's the issue, but here it is: 'https://retail.santander.co.uk/LOGSUK_NS_ENS/BtoChannelDriver.ssobto?dse_operationName=LOGON&dse_processorState=initial&redirect=S'

" Additionally, your issue may be too Linux specific for me right now so hopefully someone else can help out. Since there are a number of other support questions with regard to Firefox crashing on Linux, I feel there must be some bug involved. (If you use Flash, this bug may be a lead or related.)" That's the feeling I have, Awful Adobe strikes yet again!

"Checking for updated packages as well as the system requirements may help." I have interrogated Synaptic and Update Manager - both report no updatable files.

"Could you also report your Linux/Ubuntu version?" Running Firefox 54.0 (32-bit) [= 54.0+build3-0ubuntu0.14.04.1] on ubuntu 14.04. The only plugin is Adobe Flash Player Shockwave Flash 26.0 r0 v. 26.0.0.131 [reported by Synaptic as up-to-date]

This may be relevant: In order to revert to my 'proper' profile I again invoke firefox -P in Terminal I happily change the default in the Profile Manager and it loads & works fine BUT I notice that Terminal reports the following output:

(firefox:3365): GLib-GObject-CRITICAL **: g_object_ref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_unref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_ref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_unref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_ref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_unref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_ref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_unref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_ref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_unref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_ref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_unref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_ref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_unref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_ref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_unref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_ref: assertion 'object->ref_count > 0' failed (firefox:3365): GLib-GObject-CRITICAL **: g_object_unref: assertion 'object->ref_count > 0' failed ATTENTION: default value of option force_s3tc_enable overridden by environment. WebGL(0x867a6400)::ForceLoseContext

Thanks for your continuing attention!