Outlook Messages Sources taking up huge amount of space

Hello all,

Desperately looking for a solution - this folder: /Users/JLG/Library/Group Containers/UBF8T346G9.Office/Outlook/Outlook 15 Profiles/Main Profile/Data/Message Sources, is currently sitting at 76GB of data. 

I have plenty of emails (+/- 4000), but considering that all attachments to these messages is sitting at 2,4GB, the size of this Message Sources folder seems beyond ridiculous. 

What can I do? Running Outlook 15.31 on my Macbook Air [El Capitan], through an Office 365 Subscription, which is connecting to our work email through IMAP as an Exchange Account [Preference/Internet Accounts]. 


Hi Jordan-L-G,

The message sources didn’t only contain the emails and attachments. It also contains the cache and settings in the Outlook for Mac app. So it could have a larger size then the size of all the emails and their attachments.

Then as you said your account is connecting to the work email through IMAP as an Exchange Account [Preference/Internet Accounts], could you let us know how exact the account was configured, via IMAP or Exchange mode? Please capture a screenshot of the detailed account type as the screenshot below:

Generally, if you are using an Office 365 for Business account, it is recommended to add the account via Exchange mode. So I would suggest you create a new profile and then add the account into this new profile via Exchange mode.
Note: please backup the email data before creating a new profile.


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Question Info

Last updated November 20, 2020 Views 3,381 Applies to: