All settings in Mikrotik sunddently disappeared for several times during these few weeks, it seems like a crash,and after I re-import the settings,it would work perfectly again. Since I installed the Mikrotik in CF card , not hard disc,so I don't know whether it is peculiar with my CF card or it would happens in hard disc also? I haven't any experience to install Mikrotik in hard disc before,did any friend met this case before in CF card or hard disc?

I wonder that if this is the matter of my CF card, why all settings include in "firewall","ip-routes","interface" all gone but scripts in "file-list" are still there. Does not all these settings exist in CF card , just dwell in memory?
If this is the matter about the CF card , Why there is no any problem with the Mikrotik itself? It just simply the settings which in it disappear.

is autosupout generated on crash?

are you sure nobody did "system reset" here ?

Thank you very much Chupaka. After read your answer, there are still three questions.
Question one:
If it is just reboot the router owing to kernel panic or hardware malfunction, why the settings in harddisc is gone? IF just reboot, settings will still be there,right? Does these settings only exists in memory?
Question two:Why there is no "reboot" options in my router? Does it only available in Mikrotikboard ?
Question three:How to open the "autospuout.rif" to examine the reason of reboot? Is it meant to be not open ? Thanks

are you sure nobody did "system reset" here ?

Only I use the router,no other people in my home. and if it caused by "system reset", I wonder that why the settings in router would gone ? and the facts is that when it happened, I am sitting in front of the router downloading at a speed of 4M,when I find that I can't log on,so I check the router, and "reset" manually.
"Reset" it not a problem,the key point is why the settings in harddisc would disappear? and it's not happened once,at least several times.It's awful.

How to open the "autospuout.rif" to examine the reason of reboot?

no way. only support@mikrotik.com can do that