Visual Studio 2015 Intellisense not working

Question

I have a fresh install of VS2015 on windows 8 and intellisense doesn't work at all (nothing!) in any environment.

I also have VS2013 (with Resharper 8)on the same machine which works fine.

Any ideas before I go through a re-install?

Answer 1

Make sure Tools -> Options -> Text Editor -> C# -> IntelliSense -> "Show completion list after a character is typed" is checked. I had installed and uninstalled VS 2017 and that's when IntelliSense stopped working in VS 2015 for me.

Answer 2

How I fixed it:

I went to Tools -> Extensions and Updates and uninstalled every extension I wasn't using. There were only about 3 of these. One I remember removing was "Microsoft Office Extensions", or something like that. I don't have either resharper or Xamarin, which I've seen mentioned in relation to this. When I'd finished Visual Studio restarted itself, and XAML intellisense was back! Relief...

It may be the case that all you need to do is uninstall any one extension, and the resetting that VS does after that fixes the problem.

Further detail:

I don't recall changing anything specifically (eg. installing anything), when this problem suddenly appeared. I suspect it was due to a Windows update. I was really worried about this one!

I tried restarting VS, and restarting my PC, several times without success, and also checked my intellisense settings. I tried the suggestion of unchecking them and checking again.

My F# code had also lost intellisense. C# was fine, except for XAML.

It was in all VS2015 projects.

Version: Visual Studio 2015, Windows 10. January 2018.

Answer 3

I might be kind of late for the party, but hopefully this helps out anyone.

Please note, the below is just one possible cause for the issue described in this topic.

Your issue might be that you have one project/library referencing the other, but the Target Frameworks are different.

Make sure the frameworks are compatible and see if intellisense picks up your using references, etc.

Answer 4

Probably the problem is with ReSharper, I'm running VS2013 and VS2015 on the same machine without any issues.

I would try: In Visual Studio 2015, go to 'Tools | Options | Text Editor | C# | General both "Auto list members" and "Parameter information" should be checked.

If that doesn't work I would try to disable ReSharper in VS2013 and try to get the normal intellisense working. Same procedure as above if ReSharper fails to restore the settings.

Answer 5

Note: Only do this as a last resort, because it will reset virtually all of your user preferences, including where your toolbars are, environment fonts etc.

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I reached here because my intellisense was giving 1000's of errors in the Error List after installing Visual Studio 2015 on a clean Windows 7 machine.

The answers here did not apply to me, but this answer on StackOverflow: Razor intellisense not working in VS 2015, worked for me.

Run this command from the VS "IDE" folder:

devenv.exe /resetuserdata

When I restarted Visual Studio it took several minutes to "prepare Visual Studio 2015 for the first time", and when I reloaded the project all the intellisense errors had gone.

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For info, this is how I navigate to the command prompt:

Right-click the Visual Studio 2015 shortcut on the start menu to get the context menu:

Select 'Open file location' to open a new Explorer window:

Left-click anywhere on the white to deselect devenv.exe, then shift + right-click to bring up the extended context-menu, then select 'Open command window here':

Then paste the command: devenv.exe /resetuserdata

When Visual Studio starts, it's been reset:

And when I load project, errors are gone: