I get the reply "the expression you entered contains invalid syntax".
Where did you try this expression?
The idea is to open your table in design view.
Select the date field.
In the lower pane of table design, place the expression beside the
Validation Rule property.

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Allen Browne - Microsoft MVP. Perth, Western Australia.
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>I get the reply "the expression you entered contains invalid syntax".
>
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>> >
>> > So, the logic should be that <=todaysdate