Dear Mahesh Kudale,
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
If my understanding is right, apologized situation you encountered, we do understand the inconvenience caused and apologize for it. And I just tested from my side, and it seem I cannot reproduce issue as like you described above.
Our test result
I have 2 file name the same I already upload a file to SharePoint library
I have another same name file on local I drag and drop to SharePoint library.
- Can you try with different browser see you get the same error ?
- May I know what is your permission level
- May I know your other colleges has the same issue ?
- Can you provide screenshot of the issue?
Please prove upper information I will try my best to help you.
Your understanding and patience will be highly appreciated.
If there is any misunderstanding, please feel free to correct me.
Have a nice day!
Best regards,