Hm. I do a CLEAR ALL when this happens to me. Have you tried that?

>>>>>>Frequently after running a form, when I go to the pj to modify one
>>>>>>of the classes used in the form (or the form class itself) I get the
>>>>>>error "cannot modify class in use" (syntax may be wrong). I spent
>>>>>>many hours trying to figure out where it was in use, but then
>>>>>>discovered that I can modify a sub-class of the forbidden class, then
>>>>>>then forbidden class can be modified.
>>>>>>
>>>>>>Example:
>>>>>>
>>>>>>run client.spx
>>>>>>modify class frmBase --- error
>>>>>>modify class frmData --- subclass of frmBase used by client.spx
>>>>>>close frmData
>>>>>>modify class frmBase --- works fine now
>>>>>>
>>>>>>What am I missing?
>>>>>>
>>>>>>TIA
>>>>>
>>>>>Correction
>>>>>
>>>>>Example:
>>>>>
>>>>> run client.spx
>>>>> close client.spx
>>>>> modify class frmBase --- error
>>>>> modify class frmData --- subclass of frmBase used by client.spx
>>>>> close frmData
>>>>> modify class frmBase --- works fine now
>>>>>
>>>>> What am I missing?
>>>>>
>>>>> TIA
>>>>
>>>>Addition:
>>>>
>>>>I have tried disp memo, list objects, clear all, close all, everything possible.
>>>>There is no object. If there were, I could not modify frmData. And I don't
>>>>do ANYTHING AT ALL between modify class frmDATA and modify class frmBASE EXCEPT
>>>>closing frmDATA.
>>>As far as I can understand your frmData is based on frmBase and is open at that time, right ? If so frmData is already using frmBase class.
>>
>>Nope.
>>after running and releasing the form, I try to modify frmBase, but I can't
>>because it's in use (it isn't but VFP5.0a thinks it is). In order to get VFP
>>to recognize that it's not in use I just modify a sub-class of frmBase (any one
>>will do), close it then try to modify frmBase again, and it works fine.
>It's so strange. I would like to learn the reason too. Didn't face at all.