You should probably use XCOPY and copy the C:\Users\<accountnames> folder(s), at least - you can ignore the 'Default' and 'Default User'folder, as it should contain nothing of importance (and one of them is merely a junction).
What email client are you using? - check its archive folder, and copy that as well - some (such as Windows Mail and variants) hide the data within the Windows folder tree, rather than in the sensible place.
I did actually do a disk copy recently to clone a data drive that wouldn't do it any other way - it seems to have worked perfectly, as I'm using it now
The command I used was
robocopy <source> <dest> /S /COPYALL /NP /LOG:C:\robolog.txt /TEE
which creates a log file and shows the progress on-screen