The setup for this installation of visual studio is not complete, really?
If you have an offline installation like me and can't simply re-run the Visual Studio Installer you can edit devenv.isolation.ini and change the last line to read SetupFinished=true. It will detect your trickery and complain, but at least it will launch again.
Edit: I ended up getting the Visual Studio Installer to fix the issue after choosing the "Download then Install" option. Maybe I was too impatient when I initially stopped the update? My above answer is useful when you need to get work done that isn't affected by the broken features, but you will likely encounter problems later on.
In this case you need to go to the Control Panel => Programs and Features and choose Visual Studio and update it.
VS 2017 (15.6.6) was fine for me on Friday 6/1/18 on Windows 10, but same issue as OP today after a restart.
As suggested by the dialog and Retired Ninja, I ran the Visual Studio Installer (to 15.7.3 after updating VS Installer) and that fixed it.
Note that the 15.7.3 update was a 7.73 GB download. Your download size may vary.
This has happened to me for the last 3 upgrades in Visual Studio Enterprise 2017 (now again on upgrade to 15.9.21). The fastest fix (and I'm not sure why) is simple and doesn't bomb your settings or take for ever.
- In the Visual Studio Installer, click on Modify.
Click "Modify" on the bottom right corner. Yes it says "Total space required 0 KB". Yes you didn't really change anything.
It will then act like it is downloading something. (not sure what)
- It will then act like it is installing something. (again, not sure what)
- Open Visual Studio 2017 and it works.
Hope this helps.