permissions for robocopy..

ok, when i tried with /L option:
C:\Users\mosv>Robocopy c: \users z:\RCB /copyall /Mir /r:5 /w:15 /zb /L
i get the below: why is it confused on parameter 3? it is trying to copy default profile (C:\Users\mosv\)to the root directory(C:\Users\mosv\)? while i wanted to move C:\Users to z drive. (z drive is available as can be seen in the script below)
-------------------------------------------------------------------------------
   ROBOCOPY     ::     Robust File Copy for Windows

-------------------------------------------------------------------------------

  Started : Sat Jun 27 20:14:17 2015

   Source - C:\Users\mosv\
     Dest - C:\users\

    Files :
  Options : /COPY:DAT /R:1000000 /W:30

------------------------------------------------------------------------------

ERROR : Invalid Parameter #3 : "z:\RCB"

       Simple Usage :: ROBOCOPY source destination /MIR

             source :: Source Directory (drive:\path or \\server\share\path).
        destination :: Destination Dir  (drive:\path or \\server\share\path).
               /MIR :: Mirror a complete directory tree.

    For more usage information run ROBOCOPY /?


****  /MIR can DELETE files as well as copy them !

C:\Users\mosv>
~~~~~~~~~~~~~
C:\Users\mosv>dir z:\
 Volume in drive Z has no label.
 Volume Serial Number is 76B2-6274

 Directory of z:\

06/27/2015  07:07 PM    <DIR>          .
06/27/2015  07:07 PM    <DIR>          ..
06/27/2015  07:07 PM    <DIR>          RCB
               0 File(s)              0 bytes
               3 Dir(s)  646,300,110,848 bytes free

C:\Users\mosv>

I perhaps had to give the full network path for z drive: please see below: why does it list only handful while there are 10s of 1000s of files in c:\users folder?
~~~
C:\Windows\system32>robocopy c:\users \\pr31\Users\Public /XD AppData /XJD /
R:5 /W:15 /MT:32 /L

-------------------------------------------------------------------------------
   ROBOCOPY     ::     Robust File Copy for Windows

-------------------------------------------------------------------------------

  Started : Sat Jun 27 20:37:27 2015

   Source : c:\users\
     Dest : \\pr31\Users\Public\

    Files : *.*

 Exc Dirs : AppData

  Options : *.* /L /COPY:DAT /XJD /MT:32 /R:5 /W:15

------------------------------------------------------------------------------

        *EXTRA Dir        -1    \\pr31\Users\Public\Documents\
        *EXTRA Dir        -1    \\pr31\Users\Public\Downloads\
        *EXTRA Dir        -1    \\pr31\Users\Public\Favorites\
        *EXTRA Dir        -1    \\pr31\Users\Public\Libraries\
        *EXTRA Dir        -1    \\pr31\Users\Public\Music\
        *EXTRA Dir        -1    \\pr31\Users\Public\Pictures\
        *EXTRA Dir        -1    \\pr31\Users\Public\Recorded TV\
        *EXTRA Dir        -1    \\pr31\Users\Public\Videos\
          *EXTRA File             262144        NTUSER.DAT
          *EXTRA File               5120        NTUSER.DAT.LOG1
          *EXTRA File                  0        NTUSER.DAT.LOG2
          *EXTRA File              65536        NTUSER.DAT{6c8babd1-9d1b-11e4-b5
68-e4d53dd2b029}.TM.blf
          *EXTRA File             524288        NTUSER.DAT{6c8babd1-9d1b-11e4-b5
68-e4d53dd2b029}.TMContainer00000000000000000001.regtrans-ms
          *EXTRA File             524288        NTUSER.DAT{6c8babd1-9d1b-11e4-b5
68-e4d53dd2b029}.TMContainer00000000000000000002.regtrans-ms
          *EXTRA File              65536        NTUSER.DAT{707be76d-8f08-11e4-ae
98-e4d53dd2b029}.TM.blf
          *EXTRA File             524288        NTUSER.DAT{707be76d-8f08-11e4-ae
98-e4d53dd2b029}.TMContainer00000000000000000001.regtrans-ms
          *EXTRA File             524288        NTUSER.DAT{707be76d-8f08-11e4-ae
98-e4d53dd2b029}.TMContainer00000000000000000002.regtrans-ms
                           1    c:\users\

------------------------------------------------------------------------------

               Total    Copied   Skipped  Mismatch    FAILED    Extras
    Dirs :         3         0         3         0         0         8
   Files :         1         0         1         0         0         9
   Bytes :       174         0       174         0         0    2.37 m
   Times :   0:00:00   0:00:00                       0:00:00   0:00:00

   Ended : Sat Jun 27 20:37:28 2015

C:\Windows\system32>

that helped.. it brought a listing now..
it skipped one file, it says.. is it possible to filter to see which one file is it skipping?
------------------------------------------------------------------------------

               Total    Copied   Skipped  Mismatch    FAILED    Extras
    Dirs :      1602      1553        49         0         0         8
   Files :     29559     29558         1         0         0         9
   Bytes : 118.983 g 118.983 g       174         0         0    2.37 m
   Times :   0:00:27   0:00:00                       0:00:00   0:00:27

   Ended : Sat Jun 27 20:56:31 2015

C:\Windows\system32>

ok.
in actual mode, if it encounters this kind of error, will it rollback all transactions on an error or will it commit the transactions upto that point.. is that a parameter setting?

ok. when i did in real mode: i got the below (did not use COPYALL mode).. is it possible now to restart where it left off? (due to network issue, it failed after 2.5 hrs)
~~~~
the mode i used for this were
/XD AppData
/XJD
/R:5 /W:15
/MT:32
/E
~~~~
               Total    Copied   Skipped  Mismatch    FAILED    Extras
    Dirs :      1602       103      1499         0         0         8
   Files :     29559      5369      6594         0     17596         9
   Bytes : 118.983 g  46.237 g   9.746 g         0  62.999 g    2.37 m
   Times :  78:06:28   2:36:38                       0:00:00   0:00:12


   Speed :             5488519 Bytes/sec.
   Speed :             314.055 MegaBytes/min.

   Ended : Sun Jun 28 01:43:30 2015

C:\Windows\system32>

Qlemo,  /MT:32. do you see this as a downside? (drag on performance)

does  /Z work based on timestamp? (if the file was updated between the run, will it also be transferred)

>>By having a time stamp not set, RoboCopy knows it has to copy the file. By looking at the committed file size, it knows where to start again.

what if the size did not change, but data did? is there a way to make sure it has to cover all updated files in the next run (not the ones that are already updated). would not modified date be more reliable than size alone? (size could have gone down too?)

I do not understand what you are pointing, qlemo's comment I think refers to you not setting the criteria of newer than or maxage 90 meaning files that have not changed since or within a time period exclude from processing, means that everytime the program is started it will evaluated every single file in the directory.

thanks a lot! appreciate it very much experts!