...and (just as an addendum), now that I look at it, you might want to add quotations around the '$P\$C.RAR' parameter, else you'll be rather unhappy with filenames/paths which happen to include spaces...
A -DF -R
"$P\$C.RAR
" $S
And, while I'm at it, you might want to be
very very careful of what your drive-labels happen to be if you're archiving things from root-folders, as the name of the archive for a root will be the drive label - and drive labels can contain "illegal" characters, such as ":", etc... so if you submit your command, WinRAR will happily process it, and delete all the objects, but create a dead 0-Byte file of a partial name.
For example, if my E: drive happened to be named "Alarums And Excursions ( E: )" - with the "E:" added as part of the name - if I selected a folder in the root of that drive, say "Test Folder", WinRAR will try to create a file called "E:\Alarums And Excursions ( E: ).RAR" and fail as described above. But since it doesn't know it failed, everything from "Test Folder" is completely unrecoverable, as far as I can tell.
Interestingly, if I intentionally try and create a RAR with an illegal file-name (by replacing the '$P\$C.RAR' with a static name that is intentionally wrong, like "C:\COLON_C:.RAR" WinRAR properly reports the error and doesn't attempt to create a corrupted archive.
As x2 is just passing the drive label as it's supposed to, it's not an x2 bug - so I suspect WinRAR needs slightly better error checking when it actually tries to
create the file handle, rather than just checking for "potential" errors beforehand. It would be interesting to submit this to them as a bug and see if they reply with a rude word or not, considering they probably don't go out of their way to support anything other than WinExplorer, and just assume their error-checking is sufficient, when it's... not.
But the caveat remains the same -
be very careful what your drive labels are before you submit this command on root contents.