When installing ACS you may receive an error stating "Unable to enumerate Exchange servers in the environment" an Exchange server in the environment does not have a store.
This error often occurs when the Exchange organization contains at least one Exchange server without any Information Stores.
1.Start ADSI Edit
2. Right-click ADSI Edit \ Connect To
3. Naming Context \ Configuration Container \ OK
4.Browse Configuration Container \ Services \ etc to this object:CN="<problem Exchange Server>",CN=Servers,CN=First Administrative Group,CN=Administrative Groups,CN="Organization Name",CN=Microsoft Exchange,CN=Services,CN=Configuration,DC="Domain Name",DC=com
5.Right-click this object, open Properties \ Security
6.For the account, under which they run Collaboration Services Setup, set Read Deny.
7. Please preform steps 5 and 6 for the Information Store and Storage Group. These permissions are not inherited.
8. Click OK Run Setup again (should run successfully) If needed, after setup completes, they may return the permissions to the original state.
To be resolved in the next release of Collaboration Services.