what makes the such format of network block of wpa_suppliant.conf

[root]

dear all,
   i find my wpa_suppliant works does not work in a normal way,it can't
connect to any ap, and when i open the file of wpa_suppliant.conf, i
find a network block is as follow:
    network={            
        disabled=1
    }
and sometimes i find the network block which was ok before is changed to
the up format,and at the end,all the wpa_suppliant.conf is the network
block network={            
        disabled=1
    }
i want to know what makes the wpa_suppliant to write such network block
in wpa_suppliant configure file ?
     i really need your help, thanks for advance!