diff --git a/scripts/upgrade.py b/scripts/upgrade.py
index 1345048..0593016 100755
--- a/scripts/upgrade.py
+++ b/scripts/upgrade.py
@@ -51,7 +51,8 @@ def perform_upgrade_command(version,mysql=False,yes=True):
    if len(current) == 1 and current[0] == 0: #Not installed
       print("Running installer, please don't change any default values regarding ports.")
       installer = os.path.join(seaf_home,"seafile-server-%s" % version,"setup-seafile%s.sh" % ("-mysql" if mysql else ""))
-      call(["sh","-c",installer],stdout=sys.stdout, stdin=sys.stdin)
+      while not call(["sh","-c",installer],stdout=sys.stdout, stdin=sys.stdin):
+         pass
       return 0
    script_re = "^upgrade_(\d+).(\d+)_(\d+).(\d+)\.sh$"
    run = []