Stored Passwords mysteriously disappear

[BehavioralCounselor]

Every so often (once a week or once every two weeks) when I start up Windows
Mail, I get error messages on all my e-mail accounts. Then I find that my
stored password for each e-mail account is gone, even though the 'remember my
password' is checked. After I re-enter my passwords, all works fine again,
but why do they disappear in the first place? The last Windows Update
relating to Windows Mail was for Junk E-mail Filter for May 2008. I don't
know if this has anything to do with it. Has anyone else experienced their
passwords mysteriously missing from their e-mail accounts in Windows Mail?

 

[BehavioralCounselor]

As an addendum to my previous post, All of my Windows Live Messenger accounts
also disappear!

 

[Gary VanderMolen]

This problem can be cause by a non-compatible antivirus.
Which one are you using?

 

[BehavioralCounselor]

Thanks Gary, but I don't use antivirus software on this machine.