New Post: Web Service Error in Composite

I experienced this issue as well - as far as I can see it was the file ~\App_Data\Composite\ApplicationState\SerializedConsoleMessages\ConsoleMessages.XML which got corrupted (typically happens if the web process is abruptly stopped during a file write). This is a non-critical file which cache messages to the console across application restarts. Deleting the file will eliminate the issue.

I've added a fix which should prevent this particular problem from happening again.