Thank you coming to Just Answer my name is Lachard.
The first thing I would try is a repair of your mailbox sometimes it can be a damaged profile so to do a repair could you follow these steps and let me know if it makes a difference.
Press Windows + R, type AppWiz.cpl, click OK.
2. Select Windows Essentials 2012/Windows Live Essentials, click Uninstall/Change-or-Remove.
3. Click Repair all Windows Essentials Programs.
I wanted to find out if you are still having issues with your mail client or has it been resolved.