Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

While still in Safe Mode,

In the address bar, type about:crashes<enter>.

Note: If any reports do not have BP in front of the numbers/letters, click it to submit them.

The crash report is several pages of data. We need the report numbers to see the whole report.

Using your mouse, mark the most resent 7 - 10 crash reports, and copy them. Now go to the reply box and paste them in.

For more help on crash reports, see; https://support.mozilla.org/en-US/kb/firefox-crashes-asking-support +++++++++++++++++++++++ If you can't get Firefox to open, you will have to do this the hard way.

https://support.mozilla.org/en-US/kb/mozillacrashreporter Open the file browser / explorer on your computer. Note: You may have to enable Show Hidden Folders / Files. Enter this in the address bar;

Windows: %APPDATA%\Mozilla\Firefox\Crash Reports\submitted Win 7/Vista: C:\Users\<username>\AppData\Roaming\Mozilla\Firefox\Crash Reports\submitted Win XP/2000: C:\Documents and Settings\<username>\Application Data\Mozilla\Firefox\Crash Reports\submitted

Mac OS: /Users/<username>/Library/Application Support/Firefox/Crash Reports/submitted Linux: /home/<username>/.mozilla/firefox/Crash Reports/submitted

Copy the most recent 5-7 File Names in the folder. Post the information in the reply box.

Maybe check that there is enough disk space available in the temp folder that Firefox uses to initially store the downloaded file. If you have a small root partition then you may run out of space.

I don't have any crash reports and I don't know why... I think it's because Firefox completely freezes and there's no box to report the error later...

I have 150GB root partition so I don't think that's the problem.

This bug normally happens when I download a very big .iso or something from Dropbox. I'm sorry if can't help you a lot.

Did you try Firefox in Safe mode?

If the problem is that severe that the OS crashes (hangs) as well then this happens when Firefox accesses the kernel and that makes the kernel hang.

Can you find the partially downloaded file, either in the temp folder or in the final destination. If the files is still in the temp folder then it might go wrong with copying the file to the destination. If that destination in on another partition then it isn't a simple move, but the file needs to be copied and that might make Firefox crash if it takes too long.