diff -ru a/tools/build/src/tools/mpi.jam b/tools/build/src/tools/mpi.jam
--- a/tools/build/src/tools/mpi.jam	2019-12-10 01:20:16.000000000 +0100
+++ b/tools/build/src/tools/mpi.jam	2020-09-02 13:17:22.942349254 +0200
@@ -66,6 +66,8 @@
 import type ;
 import path ;
 
+import errors ;
+
 # Make this module a project
 project.initialize $(__name__) ;
 project mpi ;
@@ -538,6 +540,11 @@
     # Set up the "mpi" alias
     alias mpi : : : : $(options) ;
   }
+
+  if ! $(.configured)
+  {
+	 errors.user-error "MPI not configured" ;
+  }     
 }
 
 # States whether MPI has bee configured