After a failed attachability check, you find a number of "zombie" databases attached to the Core server local instance. You use KB#118281 (https://support.quest.com/appassure/kb/118281) and the KB-attached SQL script to detach them. Although most of the databases are easily detached this way, a few remain.
After running the script, the error listed in SQL Management Studio is similar with the one below.
Detach database failed for Server 'APPASSURE'. (Microsoft.SqlServer.Smo)
For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=11.0.5058.0+((SQL11_PCU_Main).140514-1820+)&EvtSrc=Microsoft.SqlServer.Management.Smo.ExceptionTemplates.FailedOperationExceptionText&EvtID=Detach+database+Server&LinkId=20476
An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.ConnectionInfo)
Cannot drop the database 'AA-My_Database-78f30f73-f020-4ac4-8023-68ffb2e3763e' because it is being used for replication. (Microsoft SQL Server, Error: 3724)
For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft%20SQL%20Server&ProdVer=11.00.5058&EvtSrc=MSSQLServer&EvtID=3724&LinkId=20476
Note: You can identify the "Zombie" databases by their name. It has the AA prefix linked with hyphens to the actual database and a trailing GUID
To solve the issue you need to remove the replication settings for the culprit databases.
Assuming that you have only a few and as such you will perform the operation manually, open the Sql Management Studio and connect to the database engine.
Click on the "New Query" link on the Tool Bar
In the query panel which opens on the right side, type the following command
exec sp_removedbreplication 'AA-My_Database-cd87aa26-8d20-4b91-a97d-f8daa02e86e7'
Where "AA-My_Database-cd87aa26-8d20-4b91-a97d-f8daa02e86e7" is the name of the database.
Hit the "Execute !" button on the appropriate Toolbar (or hit the F5 key)
If the execution is successful, right-click on the database and choose Tasks from the context menu.
If necessary, click "Take Offline" (This should have been already performed by the script in KB#118281) and then click "Detach" in the same contex menu.
The Zombie Database should be gone.