When logging into the Storage Platform with the SP Console you get a popup similar to this:
Or in the AccountServer log you see a similar error:
There are one or more accounts with invalid OnDisk information, e.g. very large negative value. This throws out the StorageServer calculations used in the Console.
Run the following query to identify the account:
The problem account should be the first one listed. Locate the account in the Console and confirm it has an excessive OnDisk value. Run a quick IC with fixes on it and confirm that the Ondisk Value is now within sensible limits. Afterwards the StorageServers will show again in the Console.