diff --git a/phpBB/language/en/posting.php b/phpBB/language/en/posting.php
index 1a6866d535..4d2ce46252 100644
--- a/phpBB/language/en/posting.php
+++ b/phpBB/language/en/posting.php
@@ -46,6 +46,7 @@ $lang = array_merge($lang, array(
 	'ATTACH_COMMENT_NO_EMOJIS'	=> 'The attachment comment contains forbidden characters (Emoji).',
 	'ATTACH_DISK_FULL'			=> 'There is not enough free disk space to post this attachment.',
 	'ATTACH_QUOTA_REACHED'		=> 'Sorry, the board attachment quota has been reached.',
+	'ATTACH_DISK_FREE_SPACE'	=> 'Sorry, the PHP <samp>disk_free_space</samp> function is disabled in this system.',
 	'ATTACH_SIG'				=> 'Attach a signature (signatures can be altered via the UCP)',
 
 	'BBCODE_A_HELP'				=> 'Inline uploaded attachment: [attachment=]filename.ext[/attachment]',
diff --git a/phpBB/phpbb/attachment/upload.php b/phpBB/phpbb/attachment/upload.php
index ca83f9dabf..52f60348a9 100644
--- a/phpBB/phpbb/attachment/upload.php
+++ b/phpBB/phpbb/attachment/upload.php
@@ -296,8 +296,10 @@ class upload
 	 */
 	protected function check_disk_space()
 	{
-		if ($free_space = @disk_free_space($this->phpbb_root_path . $this->config['upload_path']))
+		if (function_exists('disk_free_space'))
 		{
+			$free_space = disk_free_space($this->phpbb_root_path);
+
 			if ($free_space <= $this->file->get('filesize'))
 			{
 				if ($this->auth->acl_get('a_'))
@@ -315,6 +317,16 @@ class upload
 				return false;
 			}
 		}
+		else
+		{
+			$this->file_data['error'][] = $this->language->lang('ATTACH_DISK_FREE_SPACE');
+
+			$this->file_data['post_attach'] = false;
+
+			$this->file->remove();
+
+			return false;
+		}
 
 		return true;
 	}