I had a customer who was confused as to why a checkbox was being checked or unchecked at seemingly random times.

In this particular case, the checkbox label was very wide and butted right up to the button to save the data on the form and close it.

In Access, when you create a checkbox, it creates a label that is attached to the checkbox.  The checkbox will be checked or unchecked if either you check on the checkbox itself OR you click on the label.

Because of this behavior, my label was very wide, even beyond the text in the label.  Even clicking on a blank portion of the label, it would still check or uncheck the associated checkbox, creating the undesired behavior for the customer.

All I had to do was shorten the width of the label.  But then I went to an additional level and detached the label entirely from the checkbox, which in that case will remove the behavior of clicking on the label.

Very quick fix, but made a huge difference for the application users!