diff --git a/src/Composer/XdebugHandler.php b/src/Composer/XdebugHandler.php
index fa766122f..35581acf6 100644
--- a/src/Composer/XdebugHandler.php
+++ b/src/Composer/XdebugHandler.php
@@ -79,6 +79,11 @@ class XdebugHandler
                     putenv('PHP_INI_SCAN_DIR');
                 }
             }
+
+            // Clear version if the restart failed to disable xdebug
+            if ($this->loaded) {
+                putenv(self::ENV_VERSION);
+            }
         }
     }
 
diff --git a/tests/Composer/Test/XdebugHandlerTest.php b/tests/Composer/Test/XdebugHandlerTest.php
index 3dd1e9f53..addfe8da0 100644
--- a/tests/Composer/Test/XdebugHandlerTest.php
+++ b/tests/Composer/Test/XdebugHandlerTest.php
@@ -113,6 +113,12 @@ class XdebugHandlerTest extends \PHPUnit_Framework_TestCase
         $xdebug = new XdebugHandlerMock($loaded);
         $xdebug->check();
         $this->assertEquals($xdebug->testVersion, getenv(XdebugHandlerMock::ENV_VERSION));
+
+        // Mimic successful restart
+        $loaded = false;
+        $xdebug = new XdebugHandlerMock($loaded);
+        $xdebug->check();
+        $this->assertEquals($xdebug->testVersion, getenv(XdebugHandlerMock::ENV_VERSION));
     }
 
     public function testEnvVersionWhenNotLoaded()
@@ -124,6 +130,19 @@ class XdebugHandlerTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals(false, getenv(XdebugHandlerMock::ENV_VERSION));
     }
 
+    public function testEnvVersionWhenRestartFails()
+    {
+        $loaded = true;
+
+        $xdebug = new XdebugHandlerMock($loaded);
+        $xdebug->check();
+
+        // Mimic failed restart
+        $xdebug = new XdebugHandlerMock($loaded);
+        $xdebug->check();
+        $this->assertEquals(false, getenv(XdebugHandlerMock::ENV_VERSION));
+    }
+
     public static function setUpBeforeClass()
     {
         // Save current state