Hello everyone and thanks for your help in advance.  I am upgrading from Exchange 2003 to Exchange 2013 and need to transfer approximately 40 mailboxes.  Each user has local OST files on their client machines.  I know there is no direct upgrade from 2003 to 2013 and would prefer to do a new install rather than upgrading to 2010 then to 2013.  I know I can use a third party converter to convert the OST to PST, then import them to Exchange.  But I was wondering what would happen if I performed the new install, then set up the new mailboxes for each user on the new Exchange box, then connect the users.  Will the local OST files populate the Exchange mailboxes?  Or will Exchange overwrite the local OST files with blank data?  Or will nothing happen.  Any insight would be greatly appreciated.

Seriously, stand up an Exchange 2010 server and migrate to it first.  By doing this cheaply you're likely to end up with a system that's going to be unsuitable in several ways.

Hi,

If I were you, I will do the migration that Microsoft suggested.

And the Microsoft Exchange Server Deployment Assistant tool might be helpful for you.

https://technet.microsoft.com/en-us/office/dn756393.aspx

Best Regards.

If you're installing new Ex2013 server, then I believe you don't have to worry about ost data loss. It's very common. Simply create mailbox and assign user to it. And, then import pst (mailbox data) to any user. There is nothing wrong. But do not make any changes on your original ost file, simply create a replica then export pst to Exchange 2013.

Go ahead!

As you already know you cant go from 2003 to 2013 in Exchange. You must either go to 2007 or 2010 first for more check this: http://exchangeserverpro.com/upgrading-to-exchange-server-2013/

The above suggested reference i.e. Microsoft Exchange Server Deployment Assistant also looks good to get this job done.

Alternatively, exporting to a PST and importing from a PST also works smoothly. In case if  you have public folders you will also need to export and import public folders with permissions and recreated e-mail addresses.

Moreover, If you wish to accomplish this migration task automatically, you may try this automated solution which lets you to migrate straight from exchange 2003 to 2013 without any interruption and data loss.

Hope it helps you!

If you're installing new Ex2013 server, then I believe you don't have to worry about ost data loss. It's very common. Simply create mailbox and assign user to it. And, then import pst (mailbox data) to any user. There is nothing wrong. But do not make any changes on your original ost file, simply create a replica then export pst to Exchange 2013.

Go ahead!

• Marked as answer by kmcnet 10 hours 46 minutes ago

As you already know you cant go from 2003 to 2013 in Exchange. You must either go to 2007 or 2010 first for more check this: http://exchangeserverpro.com/upgrading-to-exchange-server-2013/

The above suggested reference i.e. Microsoft Exchange Server Deployment Assistant also looks good to get this job done.

Alternatively, exporting to a PST and importing from a PST also works smoothly. In case if  you have public folders you will also need to export and import public folders with permissions and recreated e-mail addresses.

Moreover, If you wish to accomplish this migration task automatically, you may try this automated solution which lets you to migrate straight from exchange 2003 to 2013 without any interruption and data loss.

Hope it helps you!

• Marked as answer by kmcnet 10 hours 46 minutes ago

Thanks for the response.  When all was said and done, I did the new Exchange 2013 install, then pushed the mailboxes to PST files, then imported on the server.  Worked great without a hitch.  Fortunate I didn't have too many boxes.  Thanks to all for the help.