Open file in existing instance of Visual Studio 2017
I used to be able to open a file in an existing instance of VS - devenv.exe had a /dde switch for that. But with VS2017 it opens the file in a new instance, not the one already running. For example for json files: My registry has a key HKEY_CLASSES_ROOT\.json\OpenWithProgids which contains a value VisualStudio.json . And there is a key HKEY_CLASSES_ROOT\VisualStudio.json\shell\Open\Command which contains the default value "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\devenv.exe" /dde . But that /dde is ignored. Maybe all the betas and RCs corrupted something. My