Data field is missing after renaming the file

Hello,  i inherit a filename daily i.e Active-Zoning-Host_2015_07_10_13h53.xls   I rename the file to ActiveZoning-LATEST.xls and refresh the report.

The datafield DataSource is ALWAYS missing following the rename, and i have to re-create the report again/resave.

This is the file/datafields before the rename :-

This is the datasource pulled into Crystal as an Access/Excel (DAO) datasource, Type =  Excel 8.0

using the file name directly asis.

Now i rename the file to ActiveZoning-LATEST.xls and use it as  an Access/Excel (DAO) datasource, Type =  Excel 8.0

But now the field DataSource is missing

But the field is present in the renamed file:-

Any idea what is going on ?  Thanks