Topic Status: Some information in this topic is preview and subject to change in future releases. Preview information describes new features or changes to existing features in Microsoft SQL Server 2016 Community Technology Preview 2 (CTP2).
This informational message indicates that the index cannot be checked because one of the filegroups that stores data for the index is offline. The state of the files in a filegroup determines the availability of the whole filegroup. For a filegroup to be available, all files within the filegroup must be online. If there are no other problems, all other indexes of the same object will be checked.