VS2010 Intellisense behavior change (not fixed by ctrl-alt-space)

All of a sudden I've lost automatic Intellisense in my projects. And now I'm doubting I ever had it because it's something I just took for granted.

Now, if I type in System. nothing pops up automatically until I hit ctrl-space.

I've tried the suggested "ctrl-alt-space" to toggle intellisense Completion Mode, but that only adds or removes a search box at the top of the Intellisense window, which I still have to bring up with "ctrl-space"开发者_如何学C

Am I crazy? Isn't the default mode of Intellisense to popup suggestions after you type in object. ?

It is a setting, it could be turned off if you recently played with an add-on that you subsequently uninstalled. For example. Tools + Options, Text Editor, All Languages. Ensure the "Auto list members" checkbox is ticked.

If you are using C#, go to Tools -> Text Editor -> C# -> IntelliSense. Make sure "Show completion list after a character is typed" is checked.