diff --git a/lib/private/setup.php b/lib/private/setup.php
index 4a4b935df03..2c959622cc7 100644
--- a/lib/private/setup.php
+++ b/lib/private/setup.php
@@ -434,8 +434,9 @@ class Setup {
 		}
 
 		// Add rewrite base
+		$webRoot = !empty(\OC::$WEBROOT) ? \OC::$WEBROOT : '/';
 		$content.="\n<IfModule mod_rewrite.c>";
-		$content.="\n  RewriteBase ".\OC::$WEBROOT;
+		$content.="\n  RewriteBase ".$webRoot;
 		$content .= "\n  <IfModule mod_env.c>";
 		$content .= "\n    SetEnv front_controller_active true";
 		$content.="\n  </IfModule>";