If you are using Windows 10, then you need to create a user account which will be used for your profile folder. When Windows users create a user account in Windows 10, the initial 5 characters of their live account ID will be used for naming user profile folder. For example, if smohit[@outlook.com] is your Microsoft account ID, then the user profile name will be ‘smohi’.
https://sites.google.com/a/allitemarketing.biz/windows/888-606-4841-fix-windows-10-email-program-error-rename-user-profile-folder-and-system-performance
https://sites.google.com/a/allitemarketing.biz/windows/888-606-4841-fix-windows-10-email-program-error-rename-user-profile-folder-and-system-performance
