This started maybe 4 to 6 weeks ago.

I have made no hardware changes during that time, and no new software updates (that I am aware of).

For now, I have excluded the entire folder containing all my project files. We'll see what happens.

Thanks for your help.

Jim

>Ok, ignore the program files directory and SMB2 suggestions then :o) Somehow in all these messages I got the impression you were working in Windows 7 64 bit... this very seldom happens in XP... most often the culprit when on XP is antivirus or antimalware. Exclude .sct/.scx from virus scanning as a test if you haven't already.
>
>When did this start happening?
>
>>Have already deleted FoxUser files.
>>
>>This error has not been creating C5s, it has 'merely' been destroying the form or class I was editing. However, there seem to be no other effects.
>>
>>And, SMB2 is part of Vista, no? I am still in XP.
>>
>>
>>
>>
>>>Delete your foxuser files as well.... and any leftover .tmp files from sessions that ended with a C5 and if no one else has mentioned it yet, turn off SMB2...
>>>
>>>>Thanks. Have done so.
>>>>
>>>>>>I certainly will, if I do well enough to resolve it.
>>>>>>
>>>>>>I may not know, of course, which of the actions I take have anything to do with it, as I will be trying a number of different things. Since I do not know how to intentionally cause the error, and since it occurs relatively infrequently, it will take some time to have any certainty that the problem has disappeared.
>>>>>>
>>>>>>But I will keep you posted.
>>>>>>
>>>>>>Now, back to Write Caching -- What are you suggesting that it be set to?
>>>>>
>>>>>OFF
>>>>>
>>>>>*And* make sure your app is not in your program files path. Put your app's working/development path in a path all its own off c:\ like c:\apps\myapp etc and try that.
>>>>>
>>>>>
>>>>>
>>>>>>
>>>>>>
>>>>>>>You've been given good things to try. All of these suggestions are things that have worked for most of us in the past. Can you post your results after you test each of the suggestions? Note, it may take a combination of the suggestions to resolve the issue....
>>>>>>>
>>>>>>>
>>>>>>>>OK, those look like very detailed instructions. Write caching is enabled for the disk where my apps live. How is that relevant?
>>>>>>>>
>>>>>>>>>Turn Disk Write Caching On or Off
>>>>>>>>>
>>>>>>>>>1. Right-click My Computer, and then click Properties.
>>>>>>>>>2. Click the Hardware tab, and then click Device Manager.
>>>>>>>>>3. Expand Disk Drives.
>>>>>>>>>4. Right-click the drive on which you want to turn disk write caching on or off, and then click Properties.
>>>>>>>>>5. Click the Policies tab.
>>>>>>>>>6. Clear the Enable write caching on the disk check box as appropriate.
>>>>>>>>>7. Click OK.
>>>>>>>>>8. Restart the Computer.
>>>>>>>>>
>>>>>>>>>>I have absolutely no idea. I have never done anything with write caching, nor do I know how to.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>>Is write caching disabled on all HDD in the system?
>>>>>>>>>>>
>>>>>>>>>>>>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???