First, I prepared a C5 demo as .exe file (www.eetasoft.ee/c5demo.zip)
A lot of people tried it. ALL of them except you and Mike were able to reproduce C5
error. VFP 7 beta tester, Milan Kosina, also gots C5 error from this.

Second, I prepared a source code of this demo. Dragan Nedeljkovich runs this code and was able to reproduce C5 error.

>I have tried to duplicate this error and can't. DeleteColumn works fine for me, as does reducing the ColumnCount. I'm curious about the "F3" ... are you enabling F3 as a hotkey to delete columns? If so, how?

I use the following code

DEFINE POPUP myaction MARGIN RELATIVE SHADOW COLOR SCHEME 4
DEFINE BAR 1 OF myaction PROMPT ""+I("Action") FONT (m.g_menufont),8 style "" ;
	KEY F3, "F3"
ON SELECTION BAR 1 OF myaction _screen.activeform.f3()

>
>Mark mentioned that Mike and I are interested in these posts. We are. It is of great service to us in our roles as testers to have people post what they believe are bugs, whether we can duplicate them or not or whether they are actual bugs.

>OTOH, we can't spend a lot of time here trying to duplicate an issue posted as we are not product support and resolving issues here is not within our official duties. If a problem can't be resolved by the community here, I invite you to contact product support. Product support contact info can be found in the VFP7 help file under Microsoft Visual FoxPro Technical Support.

Must I dial MS support number in my contry instead of UT ?

>>I have a command F3 "change grid form" in my form.
>>This command destroys all grid columns and then adds new columns to grid.
>>
>>To destroy columns I use
>>
>>

>>  this.gridbase1.columncount = 0  && C5 error occurs in this line
>>

>>
>>I tried also
>>
>>

>>  DO WHILE this.gridbase1.columncount>0
>>    this.gridbase1.DeleteColumn   &&& C5 error occurs in this line
>>    ENDDO
>>

>>
>>Using those commands in VFP 7 will cause C5 error sometimes. This works in VFP 5.
>>
>>Is there a way to re-create grid columns to avoid C5 error ?