diff --git a/motioneye/static/js/main.js b/motioneye/static/js/main.js
index 7f655da00..5da730bf1 100644
--- a/motioneye/static/js/main.js
+++ b/motioneye/static/js/main.js
@@ -18,7 +18,7 @@ var passwordHash = '';
 var basePath = null;
 var signatureRegExp = new RegExp('[^A-Za-z0-9/?_.=&{}\\[\\]":, -]', 'g');
 var deviceNameValidRegExp = new RegExp('^[A-Za-z0-9\-\_\+\ ]+$');
-var filenameValidRegExp = new RegExp('^([A-Za-z0-9 \(\)/._-]|%[YmdHMSqv])+$');
+var filenameValidRegExp = new RegExp('^([A-Za-z0-9 \(\)/._-]|%[CYmdHMSqv])+$');
 var dirnameValidRegExp = new RegExp('^[A-Za-z0-9 \(\)/._-]+$');
 var emailValidRegExp = new RegExp('^[A-Za-z0-9 _+.@^~<>,-]+$');
 var initialConfigFetched = false; /* used to workaround browser extensions that trigger stupid change events */