Hi,
I'm not able to reproduce what you are saying. I was able to delete an excel file that was used in a DataSource and DataSource loop after the test case finished without closing SoapUI Pro. Do you have the files that are being used by the DataSource open externally outside of SoapUI Pro? If so, that's probably why they are locked. If the files are being created by SoapUI Pro then that is probably why they are locked the entire time. Please confirm that nothing else is using the files after the test case is complete including any Groovy you may be using.
Regards,
Marcus
SmartBear Support