How to back up your Office 365 email database to your local computer

How to back up your Office 365 email database to your local computer

Summary: One of our audience members asked how to back up an Office 365 document locally. It actually turns out to be pretty simple. Read this guide for the step-by-step process (which works with other Exchange servers, too).


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    Backing up your Office 365 email database to your local computer

    A few months ago, I had the opportunity to partner up with Mike Daniels, senior solutions architect at Dell, to give a really interesting webcast on data protection.

    One of the questions we were asked by an audience member was how to back up the Office 365 email database locally. I roughly outlined the approach in the webcast, but ever since the day of the event, I've been meaning to sit down and write out the steps.

    It actually turns out to be pretty simple, as long as you're running a copy of Outlook 2010 or 2013 on your Windows 7 or Windows 8 machine. I'll also show you how you can do a similar backup process using Outlook 2011 on a Mac, but it's not a perfect solution. The Windows process works much better.

    By the way, since Office 365 is basically just a hosted Exchange service, this same set of steps will work if you're using an Exchange server somewhere else.

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    The .OST file on Windows

    Many of you who have been around the Outlook world undoubtedly know about .PST files. These are the main email database files that the Outlook client stores on local computer hard drives.

    It turns out that Exchange (which is what you're talking to when talking to Office 365) can be configured to create a similar data file, the .OST file, which also stores a local copy of your email data.

    So that brings us to four specific steps: Make sure you configure Outlook to download your entire email database; locate your .OST file; back up the .OST file; and know how to get information out of it if you need to.

    Let's look at each of these steps in turn. I'm using Outlook 2013 in my examples, but Outlook 2010 and even Outlook 2007 work similarly.

Topics: Microsoft, Security, Windows


David Gewirtz, Distinguished Lecturer at CBS Interactive, is an author, U.S. policy advisor, and computer scientist. He is featured in the History Channel special The President's Book of Secrets and is a member of the National Press Club.

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  • .ost files are surely not portable?

    I haven't tried out the process outlined above, and anyway the reference to OutlookPower talks of .pst files, not .ost files. These are rather different! In the past it has been impossible to extract info from backed-up .ost files: has this really changed? I backup my O365 folders by using the Outlook "Export to .pst" facility and then back up the resultant .pst file. It works fine, and the .pst file can easily be re-attached to Outlook if you hit problems with the live folders. Has the author found a way to extract data directly from .ost files?
    • OST to PST conversion

      Hi GWK,

      There are third party tools that can convert OST to PST, but they are not free. We had a customer that lost their Exchange mailbox server and they rebuilt every mailbox by converting all the OST files to PST and then imported them with PowerShell.
      • Limits

        Watch the inherent limits to PST file sizes
  • good

    now teach people how to import mail database into some decent mail client, meaning anything not from microshit
  • Incomplete

    Copying OST files can be problematic if you are also syncing with other devices. If you really want a backup, export the mailbox to a PST file so you have a local copy on your computer. Then you have no issues with a local cached copy of an OST file if you were to try to replace a corrupt data file.

    I found the article really lacking in any substance. You never really finished the process and it wasn't explained very well.
  • poorly explained

    I think what you are proposing is:
    1. Copy your OST file (why?)
    2. Copy data from your OST into a new PST (link to old article which is for PST to PST).

    What is the point of backing up the OST? What you should do is either use your clunky method of dragging into a different PST, or better just do File Export and export the whole mailbox to a PST. Then you have the whole mailbox and then you can take a copy.

    This is poorly explained and confusing, and basically the advice is wrong.
    • please email lets talk thanks

      need more indormation please email thanks , , we are in canada on the west coast , vancouver british columbia , canada Skype address is wiliamandwilma
      pacific coast time zone we like what you have to say about back up but need information many thanks jan 27 monday 2014 time is 12:20 in the afternoon pm
  • Still looking for real backup

    At best, the clunky, unsupported .*st file format works per user. I'm still looking for a reliable backup of an entire message store that would survive an attack on or the unlikely loss of a hosted mail store, and could be migrated to a different hosted service or to an on-premises Exchange server.
  • Better yet...

    Why not simply leave ALL your data on your hard drive? Forget this SaaS/cloud crap. You're paying monthly forever for the software and have to put up with all the cloud problems like outages, increased bandwidth costs, hacking your data, etc.

    • Cloud Storage Enables Portability

      Accessing the same email stores on ones phone, tablet, home PC, office PC, or from a friends PC at their home. Centralized storage.
      Unfortunately, I think we assume that ALL of the cloud-based providers have a HIGH URGENCY to ensure the error-free preservation of our data, even when the service is offered for low or no cost.
  • I thought we were in a post-PC world!

    Y'know...the kind where the hard drives in Teh Cloud(tm) where the reliable ones, and made sure your data was accessible from your iPad and iPhone, which is what all the cool people are using these days...and that only the browser was relevant anymore (except with everyone going to Webkit, even that's no longer relevant)? Why would you EVER need to locally back up your data! We can trust Teh Cloud(tm)! You'll get left behind if you keep copies of your own data and use an actual installed mail client!

    ...or is there merit to actually keeping data on a hard disk that you can either clone or shoot?

  • Export Outlook messages to text

    The part of most email that is worth saving is plain text. Attachments can be saved separately.
    Awhile ago I wrote a VBscript to export my Outlook mail to text files and plain folders using Outlook object model methods obj.SaveAsFile for attachments and .SaveAsTxt for text email.
    This was for an older version of Outlook (2007?) but should be re-doable today, by anyone with time and scripting ability.
    Primitive, but you won't have to worry about importing it into Outlook 2025 a decade from now.
  • Just one mailbox?

    How do I export an entire mail database with dozens of mailboxes from MSO365?
    • I'll look into it

      I haven't had to do that, but I'll look into it and add it as a potential future article. Thanks for asking.
      David Gewirtz
  • Begs A Question ...

    This article focusses on a means to ensure no data loss. Seems to question of the full utility of cloud-based storage services. HOW SECURELY or at least RELIABLY WILL THE CLOUD STORE IMPORTANT OR CRITICAL DATA?

    On reliably, I recently had moved all of my wife's emails (very few of which are important in a business sense, none critical) to a new online email provider.
    In the process of completing the transfer, the client software had an error on closing, and lost or damaged the local copy in the client store.

    When the email client was opened the next time, "there it wasn't". 90% of the transferred email, verified to be present during transfer was GONE. If this were important or critical information, the level of grumbling and shouting would readily have been heard by the service provider. As it was, there was little joy with this loss of data.

    So, how reliable do you believe your cloud storage services to be?? Do you have all of your CRITICAL and IMPORTANT cloud-stored data backed up locally in case the cloud service or local client interface s/w causes a data loss??
  • I use a 3rd party solution

    I use a solution called 'docaveonline'
    it backs up skydrive, SharePoint and exchange 365 over ftp to a local backup device. Encrypted ofcourse..

    works really well! And not really expensive definitely worth a look at.
  • I also use 3rd party solution

    I use for backing up our office 365 database. It's very easy to use - by one click I backup and also restore what I need. Not expensive at all, and very good cost- value return. I recommend it!
  • Office 365 email backup

    Well written. There are 2 backup services for office 365 data.
    "Office 265 backup" ---> This is backup of your email. Contacts and Tasks.The backup is activated using the administrator credentials.
    Other one is "Exchange online Mail Backup"--->This an email backup only. This backup is activated using the individual user credentials and it is based on IMAP interface.
    For more details you can see this blog.
    office 365 email backup