I guess you have an index on a UDF called function1. If that is the case, make a small file function1.prg:

function function1
parameter p1,p2,p3,p4
return ' '
endfunc

then

set procedure to function1 additive
use yourfile exclusive

Then you must check the index expressions, and delete the tag based on function1. After you have deleted the tag, you can

release procedure function1
eras function1.*

>thanks for help! Now I've found out that there's a function in the expression and whatever I do with the table, I get the message "the file 'function1.prg' does not exist". I used 'set safety off, set talk off', but it won't work. Any idea?
>TIA
>tomi szigeti