A difficulty in get rid of an unexpected grain ?

[Tharusha]

Please see the attached image and guide me to remove the grain in the reflective material I created.
Thanks in advance
Tharusha

[Peter.Chaushev]

Hello,

The most common fix for "fireflies" is to enable the V-Ray Asset Editor's Settings > Raytrace (Advanced view) > Optimizations > Subpixel Clamp.
If this does not amend the issue and if by chance you are using materials created in older V-Ray versions, you can pack your project (Extensions > V-Ray > Pack Project) and send it over at support@chaosgroup.com for investigation.

Kind regards,
Peter

[Tharusha]

Thank you very much