Grids will warn you when they have loaded this many records.
When grids attempt to load all available records, they normally stop and warn the user after 200 records in order to give the user the opportunity to stop the loading.
You can set this System option in Options Configuration to any number, or leave it blank if you don't want to receive a warning. If you leave this field blank, you will not be able to stop a grid from loading once it has started.