To Fix...
Ensure Outlook is set as the default Mail client
Close Outlook
For 32 bit versions of Outlook...
Delete Msmapi32.dll located C:\Program Files (x86)\Common Files\system\MSMAPI\1033\
Delete Msmapi32.dll located C:\Program Files (x86)\Common Files\system\MSMAPI\1033\
For 64 bit versions of Outlook... (I think this is the right path??)
Delete Msmapi32.dll located C:\Program Files\Common Files\system\MSMAPI\1033\
Delete Msmapi32.dll located C:\Program Files\Common Files\system\MSMAPI\1033\
Run fixmapi.exe
Open Outlook (Outlook will replace & register the Msmapi32.dll and then open).
Try the "Send To > Mail Recipient" again.