SyncToy error: cannot read from the source

Question

I am using SyncToy to copy files from my D drive to an external drive. I am using the "echo" setting, which is equivalent to Robocopy "Mirror" (if I understand correctly). Everything goes okay, but for 13 error messages that say "cannot read from the source" and list the target path as either "$recycle.bin\S-1-5-21...etc",  "found.000",  "MSOCache",  or "System Volume Information". I don't understand what this means. I have simply entered my target path as the external ("G") drive--where did all this other stuff come from? It appears that all the files have copied and appear on the ext drive.

Answer 1

No one else replied, but I found an answer. I was trying to copy an entire drive, but it doesn't seem to work that way. If I set it up to copy individual folders (like "Documents" or "Music"), everything works fine.