diff --git a/htdocs/install/check.php b/htdocs/install/check.php
index 112f742214d..81adf74f33c 100644
--- a/htdocs/install/check.php
+++ b/htdocs/install/check.php
@@ -252,8 +252,14 @@ if (! file_exists($conffile))
 }
 else
 {
+	if (dol_is_dir($conffile))
+	{
+		print '<img src="../theme/eldy/img/tick.png" alt="Warning"> '.$langs->trans("ConfFileMustBeAFileNotADir",$conffiletoshow);
+
+		$allowinstall=0;
+	}
 	// File exists but can't be modified
-	if (!is_writable($conffile))
+	elseif (!is_writable($conffile))
 	{
 		if ($confexists)
 		{
diff --git a/htdocs/langs/en_US/install.lang b/htdocs/langs/en_US/install.lang
index 23048bc921f..acdddfe3f59 100644
--- a/htdocs/langs/en_US/install.lang
+++ b/htdocs/langs/en_US/install.lang
@@ -6,6 +6,7 @@ ConfFileDoesNotExistsAndCouldNotBeCreated=Configuration file <b>%s</b> does not
 ConfFileCouldBeCreated=Configuration file <b>%s</b> could be created.
 ConfFileIsNotWritable=Configuration file <b>%s</b> is not writable. Check permissions. For first install, your web server must be granted to be able to write into this file during configuration process ("chmod 666" for example on a Unix like OS).
 ConfFileIsWritable=Configuration file <b>%s</b> is writable.
+ConfFileMustBeAFileNotADir=Configuration file <b>%s</b> must be a file, not a directory.
 ConfFileReload=Reload all information from configuration file.
 PHPSupportSessions=This PHP supports sessions.
 PHPSupportPOSTGETOk=This PHP supports variables POST and GET.