When the EMC (exchange management console) is launched, it returns the following error:

--------------------------------------------------------
Microsoft Exchange Warning
--------------------------------------------------------
The following warning(s) were reported while loading topology information:

get-PublicFolderDatabase
Completed

Warning:
Object AAA-EX01\Second Storage Group\Public Folder Database has been corrupted and it is in an inconsistent state. The following validation errors have occurred:

Warning:
PublicFolderHierarchy is mandatory.

Warning:
PublicFolderHierarchy is mandatory.


--------------------------------------------------------
OK
--------------------------------------------------------

Trying to mount the Public folder database gets you the following eror:

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Microsoft Exchange Error
--------------------------------------------------------
Failed to mount database 'Public Folder Database'.

Public Folder Database
Failed
Error:
Exchange is unable to mount the database that you specified. Specified database: UDC-EX01\Second Storage Group\Public Folder Database; Error code: MapiExceptionADPropertyError: Unable to mount database. (hr=0x80004005, ec=2418)

--------------------------------------------------------
OK
--------------------------------------------------------

When trying to delete the public folder database:

--------------------------------------------------------
Microsoft Exchange Error
--------------------------------------------------------
The public folder database 'Public Folder Database' cannot be deleted.

Public Folder Database
Failed
Error:
The critical property 'PublicFolderHierarchy' is missing in the PublicFolderDatabase object 'UDC-EX01\Second Storage Group\Public Folder Database'.

--------------------------------------------------------
OK
--------------------------------------------------------

This all happens after you deleted the "First administrative group" in ADSIedit (which you should not have done!) after a migration to Exchange 2007. If these are the only problems you are facing be happy. To resolve it perform the following actions:

1. Open ADSIedit.exe.

2. Right click on Exchange Administrative Group (FYDIBOHF23SPDLT)
3. Select New Object.
4. Select msExchPublicFolderTreeContainer for the class and click Next
5. Enter the following for the value: Folder Hierarchies, click Next
6. Click Finish

Create Public Folder Tree Object

1. Right click CN=Folder Hierarchies -> New Object
2. Selected msExchPFTree for the class
3. For the value we entered, "Public Folders" and clicked next
4. Clicked on the "More Attributes" button, selected msExchPFTreeType and set the value to 1.


Note: This is very important that this value is set to a value of 1 as this tells Exchange that this is a MAPI Tree
5. Click Ok and then finish


Populate msExchOwningPFTreeBL attribute object of the PF Stores in the organization

1. Get properties of the newly created "Public Folders" Tree object in ADSIEdit.
2. Copy the distinguishedname value to the clipboard and then click cancel.
3. Browse to CN=Public Folders Database,CN=Second Storage Group,CN=InformationStore CN="Sever Name:,CN=Servers,CN=Exchange Administative Group,CN=Administrative Groups,CN=ORG Name,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=Domain,DC=COM
4. In the properties of the "Public Folder Database", Edit the msExchOwningPFtree attribute and paste the content copied to the clipboard in Step2
5. Restart the Information Store Service.

 

*Update*

If you read the comments you'll see that Tim had a bit of an issue that was very similar to what was described here but not quite like it. Martina on the technet social helped him to resolve his issue by suggesting to check the msExchOwningPFTree attribute in ADSIedit! Have a look at the thread for the full details

 

http://social.technet.microsoft.com/Forums/en-US/exchange2010/thread/ac69d2f2-b8c4-40ab-9466-c6727da87fc7