The X++ debugger does not open...

... although you turned off "Execute business operations in CIL" in the "Tools > Options".

Then there is probably a runAs(...) method somewhere down the call stack.

You can find such a runAs-call by setting a breakpoint in Visual Studio, attaching to the process and running your logic again. After the runAs-call is found, you can simply go replace it with a direct static method call.

For example:

After this change, the X++ debugger will stop where needed.

Remember - this change is only for debugging purpose. You should not do that in the production code.