Index: lldb/source/Commands/CommandObjectTarget.cpp
===================================================================
--- lldb/source/Commands/CommandObjectTarget.cpp
+++ lldb/source/Commands/CommandObjectTarget.cpp
@@ -427,6 +427,10 @@
           result.AppendErrorWithFormatv(
               "Unable to find process plug-in for core file '{0}'\n",
               core_file.GetPath());
+          result.AppendMessage(
+              "note: If the passed file is a compressed file archive containing"
+              " a core file, you first need to manually extract the core file "
+              " from the archive before trying to load it.\n");
           result.SetStatus(eReturnStatusFailed);
         }
       } else {