Hi!

Relations work VERY bad for buffered tables, specially, when you going to relate two tables when one is buffered new record. After APPEND BLANK you did not used tableupdate. Than it looks like problem is in the automatic updating of the record there - because when I open the 'SET' window and try to change alias by clicking on another alias (secnd or first workarea), the same error happens. Looks like when tables are related, transaction spoils something that cause automatic updating do not work, and when you change alias records are going to refresh accordingly to the relations set, but record is not updated and something strange happened - so error is shown. You can post this to MS, but I doubt many people around here use transactions together with related tables and buffering. SET RELATION is used with tables without buffering in most cases, because with buffering relationing works bad (indexes are updated only after record is updated). So MS can suggest to do not fix this.

HTH.