diff --git a/htdocs/core/lib/functions.lib.php b/htdocs/core/lib/functions.lib.php
index 25b67455d70..e7a80627636 100644
--- a/htdocs/core/lib/functions.lib.php
+++ b/htdocs/core/lib/functions.lib.php
@@ -8923,6 +8923,7 @@ function addSummaryTableLine($tableColumnCount, $num, $nbofloop = 0, $total = 0,
 /**
  *	Return a file on output using a lo memory.
  *  It can return very large files with no need of memory.
+ *  WARNING: This close output buffers.
  *
  *  @param	string	$fullpath_original_file_osencoded		Full path of file to return.
  *  @param	int		$method									-1 automatic, 0=readfile, 1=fread, 2=stream_copy_to_stream
@@ -8937,11 +8938,11 @@ function readfileLowMemory($fullpath_original_file_osencoded, $method = -1)
 		if (! empty($conf->global->MAIN_FORCE_READFILE_WITH_STREAM_COPY)) $method = 2;
 	}
 
+	// Be sure we don't have output buffering enabled to have readfile working correctly
+	while (ob_get_level()) ob_end_flush();
+
 	// Solution 0
 	if ($method == 0) {
-		// Be sure we don't have output buffering enabled to have readfile working correctly
-		while (ob_get_level()) ob_end_flush();
-
 		readfile($fullpath_original_file_osencoded);
 	}
 	// Solution 1