Then expand File System or Exchange Mailbox depending which was failed
in the right side window you will see the list of your archives
Select one of the archives which failed and select Properties
When the properties opens select the Index Volumes tab
If you scroll left on that window you will see the Failed Items Column
This will show you if there are any missing items for the users archives
Each line in this represents an index location
If there are any items missing from any of the specific index locations you can highlight the one with the failed items, right click and select repair
EV will then try to add the missing items to the index.
When a repair is running the index will show as rebuilding, in fact it is just adding the missing items and it is not doing a rebuild
I also have a similar problem, after a bad failover in a EV cluster some indexes started to give me errors in the event log:
Event Type: Error
Event Source: Enterprise Vault
Event Category: Index Server
Event ID: 7292
The index volume has been marked as failed.
Index Volume: 15A3407290727264C8A139148C5DF188F1110000Machinename/Volume:72 (archivename)
Index Volume Path: E:\Indexing\Index01\15A3407290727264C8A139148C5DF188F1110000machinename
Due to errors accessing the index volume it has been marked as 'failed' to prevent further errors. The index volume will remain inaccessible until it has been repaired.
For more information, see Help and Support Center at http://evevent.symantec.com/rosetta/showevent.asp
There are no checksum.dat in those folders and when i tried to update index via admin console, it started to rebuild automaticly