Error: "Critical System Error System.FormatException Input string was not in a correct format"

This support note applies to:

Article ID: 28958

If you have incorrectly set negative number formats in Windows, you may get a few different errors in MYOB Practice Manager. For example:

Critical System Error
System.FormatException
Input string was not in a correct format.
This error occurs when adding a credit note or a negative miscellaneous charge, such as a discount or practice write off.
ForeignKeyConstraints Detail requires the child key values (-12) to exist in the parent table.
This error occurs when adding or editing timesheets.
There was an unexpected problem loading workpaper Review Points
This error occurs when opening a workpaper.

Set the Negative Number Format

In Windows, open Control Panel and, depending on your version and layout, click either:
- Region
- Clock and Region > Region
- Clock, Language and Region > Region
- Region and Language.
Click Additional settings.
If the Negative sign symbol field isn’t set to - (a hyphen), change it to - and click Apply.
From the Negative number format drop-down, choose -1.1.
Click OK. The changes are saved.
Close and re-open MYOB AE/AO.