All new environments starting from PU12 are using IIS Express in debug mode and often due to random issues we have to restart it using “Restart IIS Express” option in the Dynamics 365 menu. There are multiple discussions on community and yammer forums regarding these issues and Joris de Gruyter mentioned that it is possible to switch back to IIS if you have admin access (environment deployed to customer’s or partner’s own Microsoft Azure subscription), but did not explain how

All we need to do is to edit DynamicsDevConfig.xml file that could be found in ‪K:\AosService\PackagesLocalDirectory\Bin folder (drive letter could be different for your VM). Change RuntimeHostType value from IISExpress to IIS and that’s all.

DynamicsDevConfig

You may find same file under %userprofile%\Documents\Visual Studio 2015\Settings\ , however, Visual Studio rolls back any changes to RuntimeHostType if value is different to value in \AosService\PackagesLocalDirectory\Bin\DynamicsDevConfig file, so don’t try to change it for individual user.