diff --git a/install/lib/installer_base.lib.php b/install/lib/installer_base.lib.php
index 43d226aab5b33a6a9614ac3f91f933d03850dabe..9681d32e5e33ff9472852cf0d8d8da64097db030 100644
--- a/install/lib/installer_base.lib.php
+++ b/install/lib/installer_base.lib.php
@@ -3002,13 +3002,13 @@ class installer_base {
 
 			// Backup existing ispserver ssl files
 			if(file_exists($ssl_crt_file) || is_link($ssl_crt_file)) {
-				rename($ssl_crt_file, $ssl_crt_file . '-temporary.bak');
+				copy($ssl_crt_file, $ssl_crt_file . '-temporary.bak');
 			}
 			if(file_exists($ssl_key_file) || is_link($ssl_key_file)) {
-				rename($ssl_key_file, $ssl_key_file . '-temporary.bak');
+				copy($ssl_key_file, $ssl_key_file . '-temporary.bak');
 			}
 			if(file_exists($ssl_pem_file) || is_link($ssl_pem_file)) {
-				rename($ssl_pem_file, $ssl_pem_file . '-temporary.bak');
+				copy($ssl_pem_file, $ssl_pem_file . '-temporary.bak');
 			}
 
 			// Attempt to use Neilpang acme.sh first, as it is now the preferred LE client