Turn off Always Start When Debugging for all web projects (run within Nuget powershell console)

Console command

get-project -all | %{ $_.Properties | ?{ $_.Name -eq "WebApplication.StartWebServerOnDebug" } | %{ $_.Value = "False"} }

How to add to your profile

I've added this as a function in my NuGet PowerShell profile.

From the Package Manager Console:

PM> $profile  # echos path to NuGet_profile.ps1

Open that file in a text editor and add the following code:

function NoStartOnDebug(){
	get-project -all | %{ $_.Properties | ?{ $_.Name -eq "WebApplication.StartWebServerOnDebug" } | %{ $_.Value = "False"} }
	Write-Host "'Always Start When Debugging' has been disabled for all web projects."
}

To reload your profile with the changes:
PM> . $profile

To run the function:
PM> nostartondebug

Of course you can use a shorter name. Even better would be if it automatically ran it when a solution was opened...

%{ $_.Value = "False" } did not work for me. I had to use %{ $_.Value = $False }.