diff --git a/doc/man-pages/pod1/vos_restore.pod.in b/doc/man-pages/pod1/vos_restore.pod.in
index 6c5dd70f6e..701af0cbff 100644
--- a/doc/man-pages/pod1/vos_restore.pod.in
+++ b/doc/man-pages/pod1/vos_restore.pod.in
@@ -193,7 +193,8 @@ Leaves the new volume flagged as off-line in the volume database.
 
 =item B<-readonly>
 
-Flags the new volume as read-only in the volume database.
+Flags the new volume as read-only in the volume database.  This option
+is prohibited if an RW volume is already defined in the VLDB entry.
 
 =item B<-creation> <I<dump | keep | new>>
 
diff --git a/src/volser/vsprocs.c b/src/volser/vsprocs.c
index de0b900a9a..a2c00ca143 100644
--- a/src/volser/vsprocs.c
+++ b/src/volser/vsprocs.c
@@ -4542,6 +4542,7 @@ UV_RestoreVolume2(afs_uint32 toserver, afs_int32 topart, afs_uint32 tovolid,
 	    error = vcode;
 	    goto refail;
 	} else if (flags & RV_RDONLY) {
+	    /* -readonly restore is prohibited if an RW already exists */
 	    if (entry.flags & VLF_RWEXISTS) {
 		fprintf(STDERR,
 			"Entry for ReadWrite volume %s already exists!\n",