How can I Robocopy only modified files and exclude newly created files in source folder. I'm using windows 7
/XL :: eXclude Lonely files and directories
See also What does Robocopy mean by tweaked, lonely, and extra? post.
You need to try switches like : /maxlad and /minlad check this link, I think it can helps
Robocopy just copy files that have changed (in size or modified date, by default). If a file has not changed, Robocopy by default skips it, and copies nothing for the file. But if the two server have the different file systems, files are still re-copied, even though nothing has changed. You can use /fft switch, which makes the modify time comparison more tolerant (2 seconds granularity). There is a similar thread, please go through it to help troubleshoot this issue:Robocopy - want it to only copy new and updated files...http://social.technet.microsoft.com/Forums/en-US/3123bc0c-ee2e-4692-b346-769803651520/robocopy-want-it-to-only-copy-new-and-updated-files?forum=ITCG