I am having the same issue. It started when I updated from 4.17 to 4.18.0. It opens Visual Studio fine, but it doesn’t seem to “connect” to it. Building in VS2017 doesn’t hot reload in the editor. Compiling in the editor doesn’t save the changes made in VS2017, and so doesn’t compile them. I’ve tried repairing Visual Studio, running the editor and Visual Studio in administrator mode, but nothing helps. It seems to be a bug in the editor. This is what the log tells me:
LogVSAccessor: Warning: Visual Studio is open but could not be queried - it may be blocked by a modal operation
LogVSAccessor: Warning: Couldn’t access Visual Studio
LogVSAccessor: Warning: Couldn’t access module table