Warning! If you have added custom indexes to the VMware vCenter database, you will need to remove them completely before you can complete a vCenter 6.5 upgrade. If they are still present in the database, the upgrade wizard throws an error.

The error file tells you specifically which indexes it does not like. The error file is found at:

C:\Users\(youraccount)\AppData\Local\Temp\vcsUpgrade\vcdb_req.err

You’ll find the error message towards the bottom of the document. My specific item was:

1 [42000](50000) [Microsoft][SQL Server Native Client 11.0][SQL Server]ERROR ! Extra indexes: VPX_EVENT.HFX_VPX_EVENT_Cover01; VPX_STAT_COUNTER.IX_VPX_STAT_COUNTER_STAT; VPX_TASK.HFX_VPX_TASK_Cover01;

Drop the indexes and retry the upgrade and it should get past this point without a problem.

Such is the risk we all take with modifying the databases underneath third party software…