Right-Click the menu that pops up when hovering your mouse over the left bottom corner of the screen in Windows 8. Open the ‘Microsoft’ folder In the ‘Microsoft’ folder, select the Visual Studio sub-folder. One called ‘10.0’ which is the Visual Studio 2010 folder and one called ‘11.0’ which is the Visual Studio 2012 folder. Continue renaming all other folders, leaving the ‘11.0’ folder for Visual Studio 2012 as is.
Restarting Visual Studio 2012, the Intellisense is back and functioning as needed.
It literally worked the one minute, and stopped working the next.
Luckily it is easily solved and not the end of the world as we know it. I recently experienced the same issue on Visual Studio 2013.Initially I tried Tools - General and checked if ‘Auto List Members’ and ‘Parameter Information’ was enabled (which it was). This caused Intellisense to stop working, but this was just after I had installed Code Rush.