There is no error message.
During the initialization of performance counter, performance counter manages a flag which does not get set properly.
This issue has been addressed in following releases:
Enterprise Vault 12.5.3
The performance counters related to Enterprise Vault indexing intermittently stop working. When this occurs the performance counter group Enterprise Vault Index Volumes Processing all show zero even though indexing is taking place.
JIRA: CFT-3339