I did not try to export history from IE.

When Firefox's installer ran, it offered to do imports automatically. I did want to import bookmarks and cookies, I didn't care about history, I didn't know that it was going to have trouble with history, and I didn't know that importation of history was going to prevent Outlook 2003 from displaying e-mail until I terminated Firefox's installer, so I let the imports run automatically. Now I do know that problem and I do not intend to import history in any future installers.

None of this has any connection with Firefox crashing during ordinary operation of Firefox. The amount of memory used is proportional to the number of tabs but it seems to be worse for me than for everyone else, so it crashes at around 30 tabs in ordinary mode or 40 tabs in safe mode.

Regarding the crashes, someone suggested installing into a clean profile, so I explained the degree of cleanliness of the profile that I installed into in the first place -- history scrambled but everything else reasonable.

64-bit Nightly, dated 2014-08-27, is displaying all except one of my tabs. The one it can't display is a document in the Google Documents cloud. I understand that 32-bit Firefox and 64-bit Nightly can't run concurrently in the same Windows account, so I'm using Internet Explorer 10 to view that one tab. Every tab is now loaded.

64-bit Nightly is using around 3.6 GB of RAM. That's a bit more than the maximum that 32-bit Firefox could reach before it crashed, and 64-bit Nightly loaded all of my tabs where 32-bit Firefox could only load about two-thirds of them before crashing.

about:memory says that 73% is window-objects.

I didn't even remember to put Nightly in safe mode. It's running in normal mode.

Yahoo mail is working. FlashUtil64 is running. Nightly's looking more stable than Firefox at this moment.

The firefox.exe process for 64-bit Nightly, dated 2014-08-27, is using 4.7GB of RAM. I still don't know why this much memory is used by the pages I'm viewing, but good news is that 64-bit Nightly is displaying them and not crashing.

aboout:memory says that 3,757.75MB are explicitly allocated, of which 70.08% are window-objects.

I'm glad I upgraded my work PC to 12GB of RAM.

I might try 64-bit Nightly at home, to see what happens on a PC that still has 4GB of real RAM. It's not cost-effective to discard a 2GB RAM board and replace it by a 4GB RAM board, the last of the DDR2 era for around US$60. (It also looks like 6GB wouldn't be enough, but people who tried 8GB in an Inspiron 1720 said their BIOS hanged.)

Oh well, that was then.

ID: fc745540-1636-4148-abca-31d1e2140829 Signature: CInputContext::_NotifyEndEdit()

Yes, I was typing into an input field in a form's search box, and I think I had just hit the Enter key when it crashed.

It wasn't due to out-of-memory though.

64-bit Nightly updated itself to 2014-08-28 when restarting.

You can try to disable TSF.

• about:config page: intl.tsf.enable = false

• Bug 1053885 - crash in CInputContext::_NotifyEndEdit()
• http://en.wikipedia.org/wiki/Text_Services_Framework

--- http://mxr.mozilla.org/mozilla-central/source/modules/libpref/init/all.js

804 #ifdef NS_ENABLE_TSF
2805 // Enable/Disable TSF support on Vista or later.
2806 #ifdef NIGHTLY_BUILD
2807 pref("intl.tsf.enable", true);
2808 #else
2809 pref("intl.tsf.enable", false);
2810 #endif

I found that TSF stands for Text Services Framework but couldn't find what it means to enable or disable it in Firefox. However, I experimented anyway. I set intl.tsf.enable to false. I was still able to input standard Japanese into another web page and then an international language (English) into this web page so it doesn't seem to have harmed anything that I can see.

On the other hand this raises another question: Since disabling TSF doesn't seem to have harmed anything, what was TSF supposed to be doing when it was enabled?

By the way, the character string that I had typed into an input box before the latest crash was just three single-byte characters "8gb". The Windows IME mode was half-width English and numeric. No henkan (conversion) operation is needed in this mode in Windows 7, but I'm not sure if Windows passes the input through the IME regardless.

Today's crash: c670db39-7a90-4a9d-b824-3276c2140902

On restarting, intl.tsf.enable was still false, the way I set it a few days ago.

I had typed some input into a form, but the crash occurred when I clicked a button to submit the form.

Continuing to use Firefox 32-bit release at home and Nightly 64-bit at work. The machine at work has 12GB of real RAM, Nightly's process usually uses around 5.5GB, other stuff uses around 2.5GB, and total RAM usage is around 66%, but sometimes paging is still slowing things down ... but sometimes unknown reasons are slowing down Nightly.

Running Nightly in safe mode, with tsf disabled, after the process's RAM usage grows past 3GB all of its windows respond very very slowly. Sometimes it gets so slow that I have to use Windows Task Manager to kill it and start over again. Fortunately it remembers 99% of its previous session's tabs (usually 100% but occasionally less).

Running Nightly in normal mode is worse. Avira runs a JavaScript add-on in every Nightly tab, and those run slowly, so Nightly displays lots of message boxes about slow scripts. In safe mode this doesn't happen, but the windows get pretty slow anyway.

In this situation, other Windows applications are fully responsive. The slowdown is only in Nightly. It is not like things used to be when my work machine had 4GB of real RAM and paging was slowing down everything.

Does this still happen in a new and clean profile with all extensions disabled?

All extensions are disabled in safe mode.

I'll have to make a list of all the URLs in open tabs, and open them in another Windows profile on the same machine. It will take 5.5GB in the other Windows profile too, so to avoid an absolute necessity to do lots of paging, after making a list of URLs, I'll tell Nightly to exit in my usual profile. I should be able to do that at work next week.

(This is one problem that Firefox 32-bit releases 31 and 32 don't seem to have. When they slow down because of paging it's because their virtual memory really exceeds the PC's RAM.)

While copying URLs from address bars of Nightly windows in this session, Nightly's UI was so slow that this happened:

I right-click the URL in the address bar, Nightly selects the entire text and opens its context menu, I click "Copy" and then paste into a Notepad window and it is OK. Next Nightly tab, copy the second URL and it is OK. Next Nightly tab, copy the third URL and it pretended to copy just like the others, but paste into Notepad and get a duplicate of the second URL instead of the third URL. Fortunately I noticed so I could delete the duplicate in Notepad and copy again from the Nightly tab. This happened around 10 times out of around 60 tabs.

At least Nightly exited properly and remembered its tabs.

In a standard Windows account (non-administrator) I launched Nightly 64-bit for the first time, after never having used any browser other than IE in that Windows account.

While copying URLs from Notepad and opening a bunch of tabs in Nightly, I got to around 40 tabs and Nightly crashed. It looks like the crash was in the JavaScript regex compiler.

One time I remembered to hold down the keyboard's Shift key and start Nightly in safe mode. But this was not immediately after the crash. I held down the Shift key when telling the crash dialog to restart Nightly, but it did not ask if I wanted to start in safe mode or not. In order to start in safe mode, I had to right-click the Nightly icon on the desktop, then hold Shift, then select the menu entry to open the application.

I don't recall if the actions in the next paragraph were in safe mode or normal mode.

Opened a bunch of tabs, then set a few options (never remember passwords, disable JavaScript baseline JIT, disable TSF, and on restart resume from where it had left off. No extensions were present and the only plug-ins were Flash and Silverlight, both up-to-date), opened a few more tabs, and Nightly was still running but gradually getting slower and slower. The 64-bit firefox.exe process reached almost 4GB of virtual RAM, a bit less than before. Windows total RAM commitments were still around 66% of 12GB of real RAM.

It took a while for all tabs to load fully. There were a few message boxes about unresponsive scripts but I selected to let them all continue, and it looks like they did. After all tabs were fully loaded, interaction with Yahoo e-mail was moderately slow, not as bad as last week but still a bit on the painful side.

Nightly automatically downloaded its latest update. I told it to restart later because I planned to exit from the running instance, and planned to log back into my usual Windows account which is a member of the Administrators group (with UAC operating normally). After finishing with experiments, I went to the menu bar "File" - "Exit". Nightly closed all its windows. The firefox.exe process was still occupying nearly 4GB of virtual memory so I waited. Good thing I waited. Nightly's crash dialog came up and I let it send a dump.

Now back in my usual Windows account, reopened Nightly ... Oh, I haven't reloaded most of my tabs yet, that's why it's only using 1.8GB of virtual RAM and still responding quickly. Will try now to reload all tabs.

In safe mode with TSF still disabled, I opened a new tab, typed input to the Google search box in the new tab, hit Enter, and told the crash dialog to send the dump.

In safe mode with TSF still disabled, I opened a new tab, typed input to the Google search box in the new tab, hit Enter, and told the crash dialog to send the dump.

Does this look like a duplicate? Will we see a triplicate in a few minutes?

S. L. O. O. O. O. W. Windows 7 64-bit, 12GB of real RAM 66% occupied, Nightly 64-bit using 4.7GB of virtual memory, Nightly is so slow that opening a mail message in Yahoo web mail takes more than a minute, and replying or deleting or composing are impossible because there i no response to my clicks.

Windows XP 32-bit, 3GB of real RAM 25% occupied (though I've had 99% sometimes), Firefox using 176KB of virtual memory, Yahoo web mail responds instantly.

Typing this submission in Nightly reminds me of a full duplex terminal in Arpanet in 1970. I type about 20 characters ahead, and wait and wait and wait to see the echos.

Everything else on this Windows 7 PC is operating normally. Even an IE window, one tab open to view a Google document, responds at its normal speed (Google is slower than editing locally but still far faster than Nightly).