I tried to view health reports and got the error. After some ULS review I was able to resolve it fairly easily.
Event ID 2:Session “SharePointDiagnostics” failed to start with the following error: 0xC0000035
Note: It is allowed to customize the schema of Usage Database.
Central administration à Monitoring à View Health Reports à Click Go
- Login to SQL Server à Connect to SQL Server Management Studio
- Expand Databases
- Expand XX_Usage
à Programmability à Stored Procedures
Find proc_GetSlowestPages stored procedure and commenting out the WITH (READPAST) line.
- Comment Out WITH (READPAST) (Just two dashes)
- Click Execute. Messages window will show command completed successfully.
- Close SQL Server management Studio.
- Go back to Health Reports and refresh the page.
- Click Go
Issue is now fixed J