When I debugging in VS2013 update3, msvsmon.exe crashed when hit at a breakpoint.
It shows \"The debugger\'s worker process (msvsmon.exe) unexpectedly exited. Debugging
I had this error also, and I too have Astrill installed. Completely uninstalling Astrill fixed the issue.
I reached out to Astrill support, and they answered (within 2 hours) saying the correct fix is to hold Ctrl and press the "Help" button on the Astrill application, and then choose "Uninstall LSP". This has fixed the issue without needing to un-install Astrill.
I don't know what LSP is, but I presume it's some sort of proxy.