Exception crashing Visual Studio 2013

[laurentkempe]

I get the following Error since some time in Windows Logs / Application

"
Application: devenv.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.NullReferenceException
Stack:
at System.Net.FixedSizeReader.ReadCallback(System.IAsyncResult)
at System.Net.LazyAsyncResult.Complete(IntPtr)
at System.Net.ContextAwareResult.CompleteCallback(System.Object)
at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
at System.Net.ContextAwareResult.Complete(IntPtr)
at System.Net.LazyAsyncResult.ProtectedInvokeCallback(System.Object, IntPtr)
at System.Net.Sockets.BaseOverlappedAsyncResult.CompletionPortCallback(UInt32, UInt32, System.Threading.NativeOverlapped_)
at System.Threading.IOCompletionCallback.PerformIOCompletionCallback(UInt32, UInt32, System.Threading.NativeOverlapped)
"

It is weird it seems to be more often while commuting in the train with a internet connection which is quite wacky. I started to disable all visual studio plugins and still had problem.
Today as it was looking like network issue I ran fiddler monitoring devenv.exe to see where does the connection goes, and it was dropbox! Then I remembered about JetBox plugins which was active in my R# plugins. I turned it off and the problem disappeared, at least till now!