If you have an error like this: "Error reported from RE on saving the record from the area map "Cons Code". The reported error was: Unable to assign the value "8/31/2020" to the Date From field on the Constituent Code. The value 8/31/2020 is not a valid fuzzy date which is expected for the Date From field. The value should contain only numbers and optionally a date separator ('-') (in mapping Cons Code)", but your date is a valid date, you may need to change the default country settings for Importacular.
If you have already attempted the Field Settings to change the date and the date is a valid format (such as 08/21/2020 for a Canadian org), you may need to change the default country settings in your instance of Importacular.
At times, the default is copying the standard for your country set in Windows and for some reason, the Windows default format may not fit the format in your file. The good news is that you can select another default in the settings so you don't have to change your data.
Go to Application settings:
It should look like this (showing your country's default):
You can then select another setting (I've selected the US since it has the / rather than the -, but you may want to use the UK depending upon the date format that you need):
