diff --git a/modules/adfs/lib/IdP/ADFS.php b/modules/adfs/lib/IdP/ADFS.php
index e29432443de553542c6d08309296d94a923f887b..7905999ce7519be093732cbb4209d54184712639 100644
--- a/modules/adfs/lib/IdP/ADFS.php
+++ b/modules/adfs/lib/IdP/ADFS.php
@@ -113,7 +113,7 @@ class sspmod_adfs_IdP_ADFS {
public static function ADFS_PostResponse($url, $wresult, $wctx) {
print '
-<body onload="document.forms[0].submit()"><form method="post" action="' . $url . '">
+<body onload="document.forms[0].submit()"><form method="post" action="' . $url . '" enctype="multipart/form-data">
<input type="hidden" name="wa" value="wsignin1.0">
<input type="hidden" name="wresult" value="' . htmlspecialchars($wresult) . '">
<input type="hidden" name="wctx" value="' . htmlspecialchars($wctx) . '">