Several of my customers read Excel spreadsheets, Microsoft Access MDB files and even text files using DAO connections. This are simple connections made by pointing directly to the data file. Unfortunately, these direct connections are no longer supported in Crystal Reports 2020. I was hoping that might be a temporary situation, but this link on the SAP website provides confirmation:

Crystal Reports 2020 is a 64bit application, and therefore it is no longer possible to connect to Excel or Access using DAO, since there is no 64bit version of this Microsoft Technology. This is why the option “Access/Excel (DAO)” is not available in Crystal Reports 2020.

You can still connect to these data sources using ODBC or OLEDB, but you will need the new 64-bit Microsoft driver. OLEDB actually works in a similar way to DAO, but you will need to do a “Set Datasource Location” in each report to convert it from DAO to OLEDB. I posted instructions in February for using OLEDB to connect to the Xtreme Sample Database (mdb) and the steps would be similar for other types of DAO connections.

If you run both 32-bit and 64-bit versions of CR you might want to switch to ODBC connections (DSNs). With ODBC you can create a 64-bit DSN on one PC and a 32-bit DSN on another PC using the same DSN name. That way you can maintain one rpt file and it can run in both the 32-bit and 64-bit Crystal environments.