Element 'CrystalReportSource' is not a known element

I faced this problem while downgrade my application to crystal 开发者_如何学Creport 10 from 11 any one have any idea

Yes, you will need to remove the element CrystalReportSource as it does not exist in crystal report Viewer 10.

This can also be caused becuse you have many crystal reports versions on your PC. so the TagPrefix="CR" is not unique. Clear your project's refrence, just keep one version of crystal reports.