BadImageFormatException or Architecture Mismatch message when using ODBC connection

Environment

Product	Progress® Telerik® Report Server
Operating System	Windows
.Net framework	Version 4.6

Description

When the Report Server application is running in 32-bit application pool and opens an ODBC connection that uses a 64-bit driver, ODBC Driver Manager throws either a BadImageFormatException (reproduced with Oracle driver) or shows "The specified DSN contains an architecture mismatch between the driver and the application" error message (reproduced with Progress® OpenEdge® driver). The same is valid also if the Report Server is running in 64-bit application pool and ODBC uses a 32-bit driver.

Solution

If the correct version of database drivers is installed, then the Report Server's application pool should be set to run in different mode (32 or 64-bit). Report Server's application pool settings define it as a 32-bit application by default. To change it, navigate to the Report Server's application pool, open its Advanced Settings form and look for a Enable 32-bit Applications property. Change it to False to run the Report Server instance in 64-bit mode and recycle the pool.