User-2057865890 posted
Hi GeoffHome,
You could try these methods.
Clean the following cache folders and restart Visual Studio:
Clean the WebSiteCache folder (might be in C:\Users\%USERNAME%\AppData\Local\Microsoft\WebSiteCache)
Clean the Temporary ASP.NET Files folder (might be in C:\Users\%USERNAME%\AppData\Local\Temp\Temporary ASP.NET Files)
Tools > Options > Environment > General and apply the following settings

http://stackoverflow.com/a/34450140
Best Regards,
Chris