The issues was resolved. Originaly when I changed the main report, Crystal asked if I wanted to propagate the changes to the subreport. I said yes, but as mentioned the control file wouldn't open. I purged the main report and subreport and replaced this with fresh copies. When I changed the database source in the main report, I replied No to Crystals propagation request. I then changed the database source in the subreport and compiled. Executable opened report without error. Dan.