Disable data validation for Excel cells

Scenario:

You want to enter a formula in a cell in which normally only certain values are allowed, e.g. cells like "Availability".

If you insert a formula in this kind of cell, you will get the following error message:

How can this be avoided?

Procedure:

Disable data validation for the cell (or all cells of this type).

1. When the cell is selected, go to the "Data → Data validation " tab.

2. In the "Data validation" window, go to the "Error messages" tab and uncheck "Show error messages if invalid data has been entered".

Optional:

Apply this property to all cells of this type.

3. To do this, go to the "Settings" tab in the "Data validation" window and check the "Apply changes to all cells with the same settings" box.

4. Confirm the changes with "OK" and enter the formula again in the cell.