The following error is seen when launching a 64-bit .NET application during recording
Critical error "Unable to Determine AUT’s bit capacity"
LoadRunner does not support the recording of 64-bit .NET applications
The workaround is for customer to re-build and deploy the client as a 32-bit .NET application.
Use CorFlags to set the application to run as a 32-bit .NET application.
Refer to the following link for more help on using CorFlags.exe