I have a problem with Outlook 2010 and OST files.

First my exhange hosting company deleted my exchange account by accident. They've created it on another server, but can't get the data back.

Now I did make a copy of the \users\name\appdata\local\outlook directory. So I have the original OST files.

I decided to switch hosts to Office 365. During this, I stupidly deleted my account from within outlook and recreated it to point to Office 365. And only then did I learn that you can't import from OST files.

Edited to clarify:

I have a complete backup of the pc. Which folders would I need to restore to ensure that I can get exhange back it's previous state? I'm prepared to to a complete restore if necessary, but would prefer to localise the changes.


do a search for an OST to PST conversion tool. there are plenty of them out there.

  • I second this - there is no way to reattach an orphaned OST - there's too much attached metadata that needs to be present. Your best bet is to use a third party tool that converts the OST to PST. Even at that, you may lose some data. – Driftpeasant Jun 8 '12 at 19:47
  • I don't see why. I have a full backup. what's the point of that if not to use it. Are there specific directories I should restore? or should I do the whole disk? – BigBadJock Jun 8 '12 at 20:47
  • 2
    BigBadJock: an OST file isn't created as a means of providing a backup of your mailbox, it's created as a means of letting users work in Outlook while Outlook is offline and to improve Outlook performance by caching certain operations instead of maintaining a continuous connection to the Exchange server. An OST file is "tied" to the user account/mailbox for which it is created. As such, you'll need a third party software tool as mentioned in this answer in order to import it into another mailbox. – joeqwerty Jun 8 '12 at 21:51
  • But surely if I restore the PC to a state before I wiped the account, I should be ok? – BigBadJock Jun 9 '12 at 18:33
  • Could a restore work? Possibly. But using an ost to pst conversion tool is much less drastic, a lot easier, and a lot faster. Don't use a jackhammer when a finishing hammer will do. – longneck Jun 9 '12 at 20:33

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