During the installation of SMSMSE and credentials to set up the SMSMSE service account were entered. The installation produces an error "User does not have a mailbox, please change username or create mailbox for the user".
Conditions
SMSMSE is not properly escaping the space character when checking the mailbox using Exchange Management Shell.
This issue is resolved in SMSMSE version 6.5.1 and higher.
Workaround
Specify a user account that does not contain a space in the name.