Hello Amol,
These messages are built in the default FileSystemContentProvider and they are not exposed in the Localization file. In this case I recommend you to change the strings in the provider directly. For your convenience I have attached a project with the configured new provider. In the project I used the default provider
FileSystemContentProvider, and changed its class name to
CustomFileSystemContentProvider. You could find the text that you need to change in the provider and replace it with the desired one.
I hope this helps.
Sincerely yours,
Fiko
the Telerik team