diff --git a/lib/setup.php b/lib/setup.php
index 8814447f52feb4c78edc2804047af44f62990e7a..b4b07bd70e494cac213f05e08f8bc7e470ae83f9 100644
--- a/lib/setup.php
+++ b/lib/setup.php
@@ -70,6 +70,10 @@ class OC_Setup {
 			$password = htmlspecialchars_decode($options['adminpass']);
 			$datadir = htmlspecialchars_decode($options['directory']);
 
+			if (OC_Util::runningOnWindows()) {
+				$datadir = rtrim(realpath($datadir), '\\');
+			}
+
 			//use sqlite3 when available, otherise sqlite2 will be used.
 			if($dbtype=='sqlite' and class_exists('SQLite3')) {
 				$dbtype='sqlite3';