Andrus,
I don't understand why you think you need the relation and the EOF() check. If you simply use the following:

UPDATE Cursor1 ;
    SET Field1=Field1 ;
    WHERE Field1 in (select field1 from RCursor)

It appears to do what you need and that is update all records in Cursor1 with a matching record in RCursor. Unless you are running an internal function that updates something in RCursor during the Update statement, I don't think you need it.

HTH.

>Please confirm, is this VFP bug ?
>
>

>CREATE CURSOR Cursor1 ( Field1 c(10) )
>INSERT INTO Cursor1 VALUES ('HLADU' )
>INSERT INTO Cursor1 VALUES ('POOD')
>
>CREATE CURSOR RCursor ( Field1 c(10) )
>INSERT INTO RCursor VALUES ( 'HLADU' )
>INDEX ON Field1 TAG T
>
>SELECT Cursor1
>SET RELA TO Field1 INTO RCursor
>
>UPDATE Cursor1 ;
>    SET Field1=Field1 ;
>    WHERE !EOF('RCursor') AND ;
>       Field1 IN (SELECT Field1 FROM RCursor )
>* Result: 0
>* Expected result: 1
>messagebox( STR(_TALLY) )
>