First I thought it was a problem of VS2013 RC/beta but now I installed VS2013 RTM and still have the same problem: code completion does only open after I execute it manually
This happened to me after uninstalling Resharper 8.x
Solution:
Tools -> Options Text Editor -> C# -> Intellisense Ensure "Show completion list after a character is typed" is *un*checked
Tools -> Options Text Editor -> C# -> Intellisense Ensure "Show completion list after a character is typed" is checked
If none of the above suggestions work, check if you have an extension Web Essentials installed. Try removing it (and install again). Web Essentials has caused my intellisense to stop working multiple times and a simple re-install always fixes the issue for me.
Be sure that your IntelliSense is activated
Tools > Options > Text Editor > C# > Statement completion
Then, be sure Auto list members is checked and Parameter Information.
1: Try to use ReSharper 8.0.2 Best Code analysic, completion tool
2: Tools > Options > Text Editor > All Language > Make Check on Auto List members