I was demonstrating Release Management vNext today as part of a course I was delivering and I received the following error message which I had not seen before in this scenario.

Web Deploy cannot modify the file ‘Microsoft.CodeAnalysis.CSharp.dll’ on the destination because it is locked by an external process.

I am using MS WebDeploy to deploy a sample application to an Azure web site which has been working perfectly well. It turns out the fix for this is pretty easy. I just needed to log onto the Azure Portal and restart the website to remove the lock on the file.