Errors occurred during load while opening a macro

Hello,

have you checked whether your .net application is capable of opening macro-enabled files in the first place? Maybe it does not have that functionality. I'm guessing here, but there could be many issues. If the workbook has events that run when the file is opened, then that code will try to run. Does your .net app allow code execution? Is the macro enabled file known to the .net app as a trusted file?