My three Gmail accounts play the notification sound, show an envelope on the lockscreen and display a 'new unread' count on the live tile, but my Hotmail account only plays the sound and shows the count on the live tile. So I always have to unlock the phone to figure out where that sound was coming from. I know there are some limitations, but I would expect Hotmail to show the envelope.
Why doesn't my Hotmail account show a lockscreen notification envelope?
There are only 5 slots on the lock screen available for notifications, and of those only 3 are for email. 1 of those is dedicated for your Live account.
The way it is determined is by the order you added them. You will need to remove/re-add the accounts in a different order if you want to have the Hotmail account there (you will lose a different one, of course) or link email accounts.
I have 4 accounts (Live, Gmail, Hotmail, Google apps) but linked the Gmail/Hotmail accounts so I get notifications for all accounts. The downside is the linked account doesn't show which account has the email. You just get a notifications saying there is one. It is better than nothing though.
Original Source. Highlight posted below.
...There are only 5 "slots" on the lock screen for notifications and they are, moving left to right:
- Missed calls/voice mail.
- Text messaging.
- Primary Windows Live ID email.
- Email account #2.
- Email account #3.
