diff --git a/SoObjects/Appointments/SOGoAppointmentFolder.m b/SoObjects/Appointments/SOGoAppointmentFolder.m
index cfda94c82..cff8d8c03 100644
--- a/SoObjects/Appointments/SOGoAppointmentFolder.m
+++ b/SoObjects/Appointments/SOGoAppointmentFolder.m
@@ -604,8 +604,16 @@ static Class iCalEventK = nil;
   NSNumber *classNumber;
   unsigned int grantedCount;
   iCalAccessClass currentClass;
+  WOContext *localContext;
 
-  [self initializeQuickTablesAclsInContext: context];
+  /* FIXME: The stored context from initialisation may have changed
+     by setContext by other operations in OpenChange library,
+     so we keep tighly to use the current session one. Without
+     this, the login is set to nil and a NSException is raised
+     at [SOGoAppointmentFolder:roleForComponentsWithAccessClass:forUser]
+     inside [SOGoAppointmentFolder:initializeQuickTablesAclsInContext]. */
+  localContext = [[WOApplication application] context];
+  [self initializeQuickTablesAclsInContext: localContext];
   grantedClasses = [NSMutableArray arrayWithCapacity: 3];
   deniedClasses = [NSMutableArray arrayWithCapacity: 3];
   for (currentClass = 0;