Index: src/wp-admin/includes/ajax-actions.php
===================================================================
--- src/wp-admin/includes/ajax-actions.php	(revision 38166)
+++ src/wp-admin/includes/ajax-actions.php	(working copy)
@@ -3515,12 +3515,13 @@
 		wp_send_json_error( $status );
 	}
 
-	// Check filesystem credentials. `delete_plugins()` will bail otherwise.
+	// Check filesystem credentials. `delete_theme()` will bail otherwise.
+	$url = wp_nonce_url( 'themes.php?action=delete&stylesheet=' . urlencode( $stylesheet ), 'delete-theme_' . $stylesheet );
 	ob_start();
-	$url = wp_nonce_url( 'themes.php?action=delete&stylesheet=' . urlencode( $stylesheet ), 'delete-theme_' . $stylesheet );
-	if ( false === ( $credentials = request_filesystem_credentials( $url ) ) || ! WP_Filesystem( $credentials ) ) {
+	$credentials = request_filesystem_credentials( $url );
+	ob_end_clean();
+	if ( false === $credentials || ! WP_Filesystem( $credentials ) ) {
 		global $wp_filesystem;
-		ob_end_clean();
 
 		$status['errorCode']    = 'unable_to_connect_to_filesystem';
 		$status['errorMessage'] = __( 'Unable to connect to the filesystem. Please confirm your credentials.' );
@@ -3771,11 +3772,12 @@
 	}
 
 	// Check filesystem credentials. `delete_plugins()` will bail otherwise.
+	$url = wp_nonce_url( 'plugins.php?action=delete-selected&verify-delete=1&checked[]=' . $plugin, 'bulk-plugins' );
 	ob_start();
-	$url = wp_nonce_url( 'plugins.php?action=delete-selected&verify-delete=1&checked[]=' . $plugin, 'bulk-plugins' );
-	if ( false === ( $credentials = request_filesystem_credentials( $url ) ) || ! WP_Filesystem( $credentials ) ) {
+	$credentials = request_filesystem_credentials( $url );
+	ob_end_clean();
+	if ( false === $credentials || ! WP_Filesystem( $credentials ) ) {
 		global $wp_filesystem;
-		ob_end_clean();
 
 		$status['errorCode']    = 'unable_to_connect_to_filesystem';
 		$status['errorMessage'] = __( 'Unable to connect to the filesystem. Please confirm your credentials.' );
Index: src/wp-admin/includes/plugin.php
===================================================================
--- src/wp-admin/includes/plugin.php	(revision 38166)
+++ src/wp-admin/includes/plugin.php	(working copy)
@@ -782,11 +782,13 @@
 	foreach ( $plugins as $plugin )
 		$checked[] = 'checked[]=' . $plugin;
 
-	ob_start();
 	$url = wp_nonce_url('plugins.php?action=delete-selected&verify-delete=1&' . implode('&', $checked), 'bulk-plugins');
-	if ( false === ($credentials = request_filesystem_credentials($url)) ) {
-		$data = ob_get_clean();
 
+	ob_start();
+	$credentials = request_filesystem_credentials( $url );
+	$data = ob_get_clean();
+
+	if ( false === $credentials ) {
 		if ( ! empty($data) ){
 			include_once( ABSPATH . 'wp-admin/admin-header.php');
 			echo $data;
@@ -796,8 +798,9 @@
 		return;
 	}
 
-	if ( ! WP_Filesystem($credentials) ) {
-		request_filesystem_credentials($url, '', true); //Failed to connect, Error and request again
+	if ( ! WP_Filesystem( $credentials ) ) {
+		ob_start();
+		request_filesystem_credentials( $url, '', true ); //Failed to connect, Error and request again
 		$data = ob_get_clean();
 
 		if ( ! empty($data) ){
Index: src/wp-admin/includes/theme.php
===================================================================
--- src/wp-admin/includes/theme.php	(revision 38166)
+++ src/wp-admin/includes/theme.php	(working copy)
@@ -23,13 +23,16 @@
 	if ( empty($stylesheet) )
 		return false;
 
-	ob_start();
-	if ( empty( $redirect ) )
+	if ( empty( $redirect ) ) {
 		$redirect = wp_nonce_url('themes.php?action=delete&stylesheet=' . urlencode( $stylesheet ), 'delete-theme_' . $stylesheet);
-	if ( false === ($credentials = request_filesystem_credentials($redirect)) ) {
-		$data = ob_get_clean();
+	}
 
-		if ( ! empty($data) ){
+	ob_start();
+	$credentials = request_filesystem_credentials( $redirect );
+	$data = ob_get_clean();
+
+	if ( false === ( $credentials ) ) {
+		if ( ! empty( $data ) ){
 			include_once( ABSPATH . 'wp-admin/admin-header.php');
 			echo $data;
 			include( ABSPATH . 'wp-admin/admin-footer.php');
@@ -38,8 +41,9 @@
 		return;
 	}
 
-	if ( ! WP_Filesystem($credentials) ) {
-		request_filesystem_credentials($redirect, '', true); // Failed to connect, Error and request again
+	if ( ! WP_Filesystem( $credentials ) ) {
+		ob_start();
+		request_filesystem_credentials( $redirect, '', true ); // Failed to connect, Error and request again
 		$data = ob_get_clean();
 
 		if ( ! empty($data) ) {