Is it possible?

I have migrated from SBS 2003 to SBS2011. Ok, so now all my users are on a temp 2010 Exchange - how can I gat them to exchange 2013? I have the Server 2012 up and running, but when I attempt to install Exchange 2013 I get:

Microsoft Exchange Server 2013 Setup cant continue because it detected one or more Microsoft Exchange Server 2010 servers havent been upgraded to Service Pack 3 (SP3) for Exchange Server 2010. Before you can install Exchange 2013, all Exchange 2010 servers in your organization must be upgraded to Exchange 2010 SP3.

So I install Exchange Service Pack 3 on the SBS 2011 - and I'm still getting the same messa

Are all your server roles on the same box? if not are all your EX servers on SP3 ?

I have moved the FSMO roles off the SBS2011 - and the Exchange 2010 is at SP3.

You need at least Exchange 2013 CU1 for Exchange 2010 SP3 coexistence scenario.  

Ok, I have downloaded the Exchange 2013 CU2 and ran the setup from there - the problem is it is seeing a failed install of a SBS2011. The virtual machine I created and it failed was still listed in AD - I opened Active Directory - deleted from the 'Domain Controllers'. Re-ran setup and the 2013 is still seeing it.

Suggestions?

1. Have you DE-install Exchange 2003 from old SBS 2003. If you did-not, then you have to do manual cleanup from AD . search adsiedit remove exchange 2003
2. On SBS 2011 , did you upgrade Exchange SP1 to Exchange SP3 ! It is requirement. If Exchange 2010 does not exist, then you have to manually delete it from AD . Search adsiedit remove exchange 2010
3. SP3 is requirement for Exchange 2010 and CU1 is requirement for Exchange 2013. Exchange 2003 is not supported.

If you remove the server you also need to go to AD users and computers under Computer container reset the legacy computer then under MS exchange security group find the Exchange servers under members, remove the legacy server.