Good evening, 

I have a Macbook Air from 2011 and have moved from Outlook to Mail as I had to continue duplicating the mail identity and Outlook was not working properly. However my 'Message Sources' folder continues growing to a point that I hardly have 1 GB of space left. Would anybody be able to advise if I can delete the 'Message Sources' folder without affecting my emails (or Word, Excel or any Microsoft programme that I continue using) given that I will not be using Outlook any longer in this computer and I will be using Mail?

Many thanks

Ignacio