Please see https://support.mozilla.org/en-US/kb/mozilla-crash-reporter#w_viewing-crash-reports about finding your crash IDs, and post them here.

Hello, Wayne. Thanks for your help. Attached you'll find the window that appear to me when it crashes. Clicking on the "details" button, a new window appears, showing a very long text. I also find the other attached screen in my help menu.

Hope you can help me to solve this problem, because I really don't know how to read that report.

Looks like you are crashing in Windows' sound code. So there's nothing you/we can do for in Thunderbird. Except you can turn off sound in Thunderbird :)

Check your drivers?

Uhmmm. I changed the sound that plays when I receive a new email. How can I read this on the crash report? Where did you find this?

I'm on my smartphone now. Tomorrow I'll try to reset the sound to the default one.

Thank you so much.

SoundInit, is it right?

The stack shown in the crash report is all Windows code.

0 	winmm.dll	soundInitWavHdr(wavehdr_tag*, unsigned char*, unsigned long)	

1 winmm.dll soundLoadMemory 2 winmm.dll sndMessage 3 winmm.dll mmWndProc(HWND__*, unsigned int, unsigned int, long) Ø 4 user32.dll user32.dll@0x2d2b2 Ø 5 user32.dll user32.dll@0xe889 Ø 6 user32.dll user32.dll@0xe1e3 Ø 7 user32.dll user32.dll@0x2bc0f 8 winmm.dll mciwindow(void*) 9 kernel32.dll BaseThreadInitThunk Ø 10 ntdll.dll ntdll.dll@0x60718 Ø 11 ntdll.dll ntdll.dll@0x606e3

And another one of your crashes is definitely in sound - wdmaud.drv - https://crash-stats.mozilla.com/report/index/21ddaf68-8586-4480-a144-48e6e2161128

The modules tab will show you the version numbers that are loaded for drivers/dlls/etc https://crash-stats.mozilla.com/report/index/21ddaf68-8586-4480-a144-48e6e2161128#tab-modules

Thank you so much. Tomorrow morning I'll try to solve it. I'll reset the default sound and will check my sound drivers.

I reset the default sound and everything is going well now. Strange, because I'd setted a .wav file to notify me when an email arrives. With the default Thunderbird settings to the notification sound, there is no crash.

Thanks a lot for your help, Wayne.