Why does Robocopy work once and then ignore all files the next time?

Question

I used the following command:

Robocopy c:\source c:\backup /MIR /XD .svn

Then I deleted c:\backup and did it once again. This time it ignored all files and copied nothing.
Why is that?

How do I force Robocopy to copy all the files again?

Answer 1

I can only guess that the /MIR is assuming that the files are already there and not checking again. Maybe include the /FFT switch as well which uses timestamps for comparison and see if it makes a difference.

Alternatively let robocopy log what it is doing. The log file may reveal why it is currently skipping files or folders. I would use the following for troubleshooting:

Robocopy c:\source c:\backup /MIR /V /LOG:WhySkip.txt /XD .svn

Added:
/V - Verbose listing including skipped files
/LOG:file - Log output to file