You can use these methods to get an empty guid. The result will be a guid with all it's digits being 0's - "00000000-0000-0000-0000-000000000000".

new Guid()

default(Guid)

Guid.Empty

As Use Keim points out in the comments default is short for default(Guid)

You can use Guid.Empty. It is a read-only instance of the Guid structure with the value of 00000000-0000-0000-0000-000000000000

you can also use these instead

var g = new Guid();
var g = default(Guid);

beware not to use Guid.NewGuid() because it will generate a new Guid.

use one of the options above which you and your team think it is more readable and stick to it. Do not mix different options across the code. I think the Guid.Empty is the best one since new Guid() might make us think it is generating a new guid and some may not know what is the value of default(Guid).

The default value for a GUID is empty. (eg: 00000000-0000-0000-0000-000000000000)

This can be invoked using Guid.Empty or new Guid()

If you want a new GUID, you use Guid.NewGuid()