It was a bug in earlier versions ( before mu5) even if you set password never expires, it would prompt you to change in 60 days
its fixed in mu5
to disable password expirations
log in to sepm console
click on admin tab
at the bottom click on administrators
click on edit admin properties
on the right click on authentication tab
check the radio buttom password never expires, should fix the issue
User is prompted to change Administrator password at Reporting logon when set to never expire
Fix ID: 1545139
Symptom: Although the Symantec Endpoint Protection Manager Administrator's password is set as "Password never expires," the user is prompted to change the password after 60 days.
Solution: Corrected the configuration to not request password change when set to never expire.
http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2007121216360648