Originally posted by: l2abe
Read the man page for the "last" command.
You will see that the informations displaied by the command are taken from the /var/adm/wtmp file so it is possible the file is corrupted.
The wtmp file grows up indefinitely so you must ensure /var is not full.
By the way can use the the "nulladm" command in order to cleanup and recreate the wtmp file or eventually copying /dev/null over wtmp itself eg:
/usr/sbin/acct/nulladm /var/adm/wtmp
or
cp /dev/null /var/adm/wtmp
Make a search in internet and you will find a lot pages explaining how to maintain the wtmp file.
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