Resolution: Follow the below steps
Search – Sharepoint Indexing Services should be running
Navigate to the Search Settings in Shared Services
Click on the Metadata property mappings
Find the property of name ModifiedBy
Click on the modifiedBy link to go to the Edit Managed Property page.
In the edit page click on the button Add Mapping
In the crawled property selction webpage dialogue which gets open when the add mapping button is clicked, Choose Office in the Select Category combo, to filter it based on Office.
And find the property Office:8(Text) from the properties list, need to select the first property only (Here we can find more than one property listed with same name) and Click OK button to select it.
Make sure the property got mapped (check this in the Mapping to crawled properties section).
Now go back to the Metadata property mappings and click on the Office:8(Text)link.
And verify the office:8 property mapped information
And make sure that Property Set ID is showing the same value as shown above, and it is mapped to the ModifiedBy managed property.
Go Back to the Search Settings
Start Full Crawl on the content source
And there you go !! Search should return you the Modified By value in results..
Cheers …!!
