>I have a timer that fires after the form is opened. The code in the timer is This.Enabled = .F.
>Do program
>
>I want to use a checkbox to enable the timer again but the code
>ThisForm.Timer3.Enabled = .T.
>will not turn it back on.
Steve,

Where is the code;

ThisForm.Timer3.Enabled = .T.

If using a checkbox I would make the Controlsource of the checkbox Thisform.Timer3.Enabled by assiging it in the Init of the form as in;

* Form's Init
Thisform.Checkbox1.ControlSource = "Thisform.Timer3.Enabled"

Now you don't need any code, checked timer is on, unchecked timer is off.

Remember every line of code you write has to be maintained, if you can do it without code that's probably a better way.