diff --git a/jstests/disk/diskfull.js b/jstests/disk/diskfull.js
index fd3ba6a4a6d..37b0f0f506a 100644
--- a/jstests/disk/diskfull.js
+++ b/jstests/disk/diskfull.js
@@ -1,13 +1,12 @@
-port = allocatePorts( 1 )[ 0 ];
 doIt = true;
-try {
-    m = startMongoProgram( "mongod", "--port", port, "--dbpath", "/data/db/diskfulltest", "--nohttpinterface", "--bind_ip", "127.0.0.1" );
-} catch ( e ) {
+if ( !( "diskfulltest" in listFiles( "/data/db" ) ) ) {
     print( "path /data/db/diskfulltest/ missing, skipping diskfull test" );
     doIt = false;
 }
 
 if ( doIt ) {
+    port = allocatePorts( 1 )[ 0 ];
+    m = startMongoProgram( "mongod", "--port", port, "--dbpath", "/data/db/diskfulltest", "--nohttpinterface", "--bind_ip", "127.0.0.1" );
     m.getDB( "diskfulltest" ).getCollection( "diskfulltest" ).save( { a: 6 } );
     assert.soon( function() { return rawMongoProgramOutput().match( /dbexit: really exiting now/ ); }, "didn't see 'really exiting now'" );
     assert( !rawMongoProgramOutput().match( /Got signal/ ), "saw 'Got signal', not expected.  Output: " + rawMongoProgramOutput() );
diff --git a/shell/utils.cpp b/shell/utils.cpp
index 39527cb3b21..c4735ee6636 100644
--- a/shell/utils.cpp
+++ b/shell/utils.cpp
@@ -80,6 +80,7 @@ namespace mongo {
             
             string rootname = args.firstElement().valuestrsafe();
             path root( rootname );
+            uassert( 12581, "listFiles: no such directory", boost::filesystem::exists( root ) );
             
             directory_iterator end;
             directory_iterator i( root);