Check Disk Quota [1]
For Staff and Retirees:
Check your quota on HKUCC1 (Central Email/Calendar Service for Staff) - Exchange 2013 [2]
For Students:
Check your quota on HKU Connect [3]
For Graduates:
Check your quota on HKU Connect [3]
Check or temporarily adjust your quota on GRADUATE.HKU.HK [4]