>>>>>Deleted record was the solution.
>>>>>Late coworker had added a place to delete records I've never thought off.
>>>>>
>>>>>Customer seems to use this on regular base, but normaly the garbage collection catches the problem.
>>>>>
>>>>>(>ლ)
>>>>
>>>>An index on !deleted() may help
>>>>

>>>>index ..... for !deleted() 
>>>>

>>>
>>>Changing tableupdate(0, to tableupdate(.T., solved it an instance without touching the index. It was very simple. :) I will keep the FOR clause of INDEX in mind, anyway.
>>
>>INDEX... for disables Rushmore optimization
>
>I don't think so, Bill
>
>Help reads
>

>When Visual FoxPro can determine that a query should not return deleted or undeleted records, and if no unfiltered index is present, it uses INDEX ON <expression> ... FOR DELETED() or INDEX ON <expression> FOR NOT(DELETED()). 
>
>For example, the following queries are now optimized:
>

That's a surprise, Gregory.
I've always thought that any filter on the index would disable optimization.