diff --git a/SoObjects/Appointments/SOGoCalendarComponent.m b/SoObjects/Appointments/SOGoCalendarComponent.m
index 65935d164..917bf7cf9 100644
--- a/SoObjects/Appointments/SOGoCalendarComponent.m
+++ b/SoObjects/Appointments/SOGoCalendarComponent.m
@@ -210,7 +210,7 @@
   [component setComment: @""];
   [component setUserComment: @""];
   [component setLocation: @""];
-  [component setCategories: @""];
+  [component setCategories: [NSArray array]];
   [component setUrl: @""];
   [component removeAllAttendees];
   [component removeAllAlarms];