Embarrassing Miatake

I have a nightly backup script that uses xcopy to backup all the modified files of the day to local USB drives.

Then it does the same xcopy to OneDrive, which should put them all in the cloud.  It never seemed to happen.  I believe this is because the xcopy command resets the modified attribute when copying to the USB drive so nothing appears modified when I xcopy to OneDrive.  I need /a flag on xcopy to USB drive