VS 2015 Community - Not checking errors until buil

Question

Intellisense will still give suggestions, but Visual Studio will not highlight any errors until I click "Start". I can write absolute gibberish and no red squiggles will appear. However, when I do click "Start", the Error List will finally populate and the build will fail. (It will also check errors after I click "ReBuild" or "Clean Solution").

However, when I do edit the errors, the red squiggles will remain. Even when I remove the entire line, a two space long red squiggle will remain. Clicking "Start", "Rebuild", or "Clean Solution" does not make these old error highlights disappear and the Error List does not change. Only closing and restarting VS 2015 Community will clear them. Rebooting the computer did not re-enable the error checking function.

System Details: This is a fresh install of Windows 7 Pro 64bit on a Macbook Pro with Bootcamp. This is the first project I have made since installing VS 2015 Community yesterday. I am writing a Windows Forms app using C#. To the best of my knowledge, it was working fine for a few hours this morning. I have already tried resetting all my settings. I have already tried rebooting and deleting the bin/obj folders in the solution directory.

Has anyone experienced such an issue? Do you think it is an issue with my install, or did my solution get corrupted somehow?

Answer 1

A few things to try that often fix weird Visual Studio problems:

1. Restart Visual Studio.
2. Delete the .suo file. This file should be right beside the .sln file, and is a temp file used for tracking things like which files/tabs you had open in the editor between sessions
3. Clear out some temp VS cache files.

Another thing you can try is running VS in safe mode to run with all extensions disabled. This may at least hint if the problem is native to VS, or if it's one of your installed extensions that is the problem.

Answer 2

Creating a new Project caused the error checking functionality to come back. I didn't even type any new code, I only made a new, blank project and everything started working again.

I have no idea why, but if someone else encounters this issue, make a new Visual Studio project and try re-loading your old one afterwards.