If you install AutoCAD Map 2017 and afterwards Civil 2017 exporting a Map drawing (FDO layers) as CAD drawing (command: _MAPTOACAD) might fail.
In particular if a template is used when exporting. Map will perform the export but will not finish the process - the dialog box won't disappear and the process cannot be cancelled. Map still uses CPU resources and needs to be closed forcefully. The drawing will be created and can be opened - but I'm not sure if all elements have been exported or not.
I had to reinstall Map to solve the issue.
Map 2017, SP1