Get "Could not convert variant of type (Null) into type (Double)" updating date in data grid (4246445)

RESOLUTION #1:

When clicking on the cell to change the date value, do not click on the dropdown arrow to get the calender to select a date from.  Instead, double click on the cell and change the date throgh the window that pops up or manually type it in the cell.  The only time this error occurs is when selecting a date from the calender in the dropdown arrow.

RESOLUTION #2

Go to View | Toad Options | Data Grid | Data and change the date format to something that does not have MMM as the month format.

STATUS:
Issue fixed in version 12.0 of Toad for Oracle. The latest version of Toad for Oracle can be donwloaded at:
https://support.quest.com/toad-for-oracle