WhatSize version 5 has been decommissioned and is not officially supported any longer.

If you wish to upgrade to WhatSize 7 follow these instructions

The upgrade to version 7 is recommended for systems running macOS Sierra (10.12) and up.
The upgrade cost is USD $9.99 for registered users of version 6 and USD $14.99 for other users.

IF YOU ARE NOT READY TO UPGRADE TO VERSION 7 PLEASE IGNORE THIS MESSAGE.

To learn more about WhatSize please visit www.whatsizemac.com