I would like to backup all Folders/Mails that are stored locally under »On my Mac« in Mac Outlook 2016. I don’t want to backup the complete Outlook Profile over and over again. Instead only archived messages that are moved to the »On my Mac« section should be backed up.

As far as I can see, they are mixed up with all my Exchange/IMAP accounts in /Users/me/Library/Group Containers/UBF8T346G9.Office/Outlook/Outlook 15 Profiles/Main Profile/Message Sources

and also

/Users/me/Library/Group Containers/UBF8T346G9.Office/Outlook/Outlook 15 Profiles/Main Profile/Messages

Unfortunately it’s not possible to create a local archive on a separate volume e.g. on Windows Outlook (PST File). Where does Mac Outlook 2016 stores Mails (On my Mac)? This is a total nightmare for system administrations...


This is the Mac Outlook 2016 Location on Local System:

/Users//Library/Group Containers/UBF8T346G9.Office/Outlook/Outlook 15 Profiles/Main Profile/Data/MessageSources

These files are actually known as OLK File, & within these folders:

1. OLK14 MESSAGE file = stores only header information enter image description here

2. OLK14 MSGSOURCE = stores email message with attachments enter image description here

where, attachments are stored in another OLK Folder namely, (OLKMSGAttach) Since, all these email parts are stored separately, it's not possible to access data within OLK, unless you have any supported Viewer.

Suggestion: It is recommended to take archive of Outlook 2016 data :

To Archive Outlook 2016 data :

  1. Go to Tools >> Export Option
  2. The Select Items: Mails, Calendars, Contacts, tasks, Journal
  3. Then manually save Data to any destination Location that you want. enter image descripion here

Please let me know, if this resolves your query

Thanks & Regards, Bradley

  • Bradley, thanks for your follow up on my issue. Creating manual backup is not my preferred options. I would like to use recurrent incremental backups for multiple Macs. So version control is crucial in my case. Also, I don't see any way to restore from these OLK14 MESSAGE files if Outlook stores its information in one giant SQL database.
    – howdytom
    Jul 8 '18 at 22:22

You will have to look for something like:

/Users/me/Library/Group Containers/123THEID.Office/Outlook/Outlook 15 Profiles/Main Profile/Data/Messages/

You will find a lot of folders with numerical names, from 0 to 255. There doesn't seem to be any alphabetical or chronological logic to it, so it's all a dumb storage with the mapping done in some other folder or DB. A good candidate is …/Main Profile/Data/Outlook.sqlite.

  • 1
    Thank you for your reply. Yeah, although the new sqlite database offers great advantage in speed and performance, all data, including archived mails are stored in one giant SQL database. This makes it impossible to separate between old archives and the latest mail store.
    – howdytom
    Jan 1 '17 at 21:04

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