diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -1286,9 +1286,10 @@ def debuginstall(ui):
         problems += 1
 
     # compiled modules
-    ui.status(_("Checking extensions...\n"))
+    ui.status(_("Checking installed modules (%s)...\n")
+              % os.path.dirname(__file__))
     try:
-        import bdiff, mpatch, base85
+        import bdiff, mpatch, base85, osutil
     except Exception, inst:
         ui.write(" %s\n" % inst)
         ui.write(_(" One or more extensions could not be found"))
diff --git a/tests/test-install.t b/tests/test-install.t
--- a/tests/test-install.t
+++ b/tests/test-install.t
@@ -1,7 +1,7 @@
 hg debuginstall
   $ hg debuginstall
   Checking encoding (ascii)...
-  Checking extensions...
+  Checking installed modules \(.*/mercurial\)...
   Checking templates...
   Checking patch...
   Checking commit editor...
@@ -11,7 +11,7 @@ hg debuginstall
 hg debuginstall with no username
   $ HGUSER= hg debuginstall
   Checking encoding (ascii)...
-  Checking extensions...
+  Checking installed modules \(.*/mercurial\)...
   Checking templates...
   Checking patch...
   Checking commit editor...