>All my work is local (no network involved).
>
>Using Trend Micro Internet Security. (Am curious why this would be relevant and, if so, why it would just have started recently)
>
>>>I've been getting the following error message every day or so:
>>>
>>>Memo File (Form-Name).SCT is missing or invalid.
>>>
>>>This occurs after I have been working on a form, when I try to save it. It's not the same form every time or anything, so I can see no pattern.
>>>
>>>Now, obviously, the SCT had to exist when I opened the form to edit it, and I can see that it exists, so it must have become invalid.
>>>
>>>How can that happen, if I am saving it???
>>
>>What is the antivirus software you're using and are you saving locally or on the Network?

Do a good backup or your entire app's path (all directories and files in your project) and then exclude the working development path (and your foxpro temp files location) of your app from your antivirus and antimalware scanning and see if the problem goes away. I ran into problems with Trend Micro and had to switch.