Error executing commands in angular / cli

I updated my angular project 4 to 5 and everything works fine. But when I execute some command to generate classes, components, services, etc, it throws me an error, example:

ng generate class miClase 

"C:\Program Files\nodejs\node.exe" D:\AngularApp\node_modules\@angular\cli\bin\ng generate class miClase 

Error: core_1.isObservable is not a function 
core_1.isObservable is not a function    
Done

Why is this happening?