Resharper autocompletion stopped working

We've recently upgraded from ReSharper 7.1 to 8.1 and autocompletion worked after the install. Now a week later we have three developers where autocompletion stopped working. After the usual clearing of the cache and even a de-install + re-install of ReSharper. We still got no autocompletion on these machines. Even within a new C# WindowsFormsApplication autocompletion is not working.

Here is what we see:




What could be causing these problems? There were a few updates this patch-tuesday from Microsoft, but these were installed on all the machines and all of our development machines have this problem with autocompletion.