I have a Visual Studio 2012 project with a reference to a Sitecore DLL. (Sitecore is a vendor.)
For a few weeks, Intellisense has worked fine. Yesterday, after installing Patch Tuesday updates and rebooting, Intellisense no longer works for stuff in the Sitecore DLL. I don’t know whether there is a correspondence.
Intellisense still works for .NET Framework stuff. E.g., if I type string. inside a method, I get Intellisense.
The project has a reference to the Sitecore namespace defined under References in Solution Explorer. Specifically, the reference is Sitecore.Kernel, and it comes from Sitecore.Kernel.dll.
If I right click on Sitecore.Kernel under References and select View in Object Browser, I can browse the DLL just fine. Also, my project builds fine; the project has a few using statements referencing parts of the Sitecore.* name space, and it uses objects in those namespaces.
If I type using Site and press Ctrl-space, I should see Intellisense suggesting {} Sitecore, but all it shows is this:

If I attempt to use Intellisense on any object in a Sitecore namespace, I get no Intellisense suggestions.
The suggestions in other areas don’t work. For example:
- Edit > IntelliSense > Refresh Local Cache: There is no Refresh Local Cache option. Yes, I did have a CS file open, and was editing it then.
- Delete %AppData%\Roaming\Microsoft\VisualStudio\11.0\ReflectedSchemas: There is no ReflectedSchemas folder there.
- TOOLS > Import and Export Settings > Reset all settings: Did not bring back Intellisense for external stuff.
- In Visual Studio Command Prompt, run devenv /resetuserdata: Seems to have done something similar to the prior technique. Had no effect on Intellisense.
- Check TOOLS > Options > Text Editor > C#: Both Auto list members and Parameter information are checked. I think these would have been reset by the prior two steps anyway.
- Through the VS 2012 installer (Control Panel > Uninstall a program), repair the entire VS installation. Had no effect.
- Remove and add back Sitecore.Kernel under References. Had no effect.
Here’s where it gets really weird: if I open this project remotely from a different workstation–which also has yesterday’s Patch Tuesday stuff installed and rebooted–Intellisense works fine! I am referring to it using \computername\c$….
I’m not sure what else to try.
For reasons I don’t understand, I was able to get Intellisense back by creating a new project and setting it up pretty much exactly like the old project.