Assume that you have a database that contains a partitioned table in Microsoft SQL Server 2014 or SQL Server 2012. The partitions of the table are mapped to different filegroups, and some filegroup mappings are invalid. When you run the DBCC CHECKDB statement, the invalid filegroups are detected and reported in the results:
Unable to process index <IndexName> of table <TableName> because filegroup (FileGroup ID <FileGroupNumber>) is invalid.
However, the summary section doesn't report any allocation or consistency errors.
The issue was first fixed in the following cumulative updates of SQL Server:
Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. We recommend that you download and install the latest cumulative updates for SQL Server:
Note This fix only corrects the DBCC CHECKDB reporting behavior so that the invalid filegroups are reported in the DBCC CHECKDB summary as consistency errors. The fix doesn't fix invalid filegroup or consistency errors, and restoring database from the last known good backup is recommended to correct the corruption.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.