Open Preset opens up a file open dialog where you can select an existing Preset.

Once a Preset has been selected the Open Preset window will appear.

Click Open to close all open inputs and replace them with this Preset.
Any settings included with the Preset will also be applied (See here for more information)

Click Append to add the inputs in this Preset to the existing session.
Any settings included with the Preset will be ignored.

Each input can be unticked if you want to exclude it from being added

Missing Files

If a preset is opened with one or more files missing, the following will appear:

High light each item in red and a Locate File button will appear. Click this button to browser for the file. If the file cannot be found, it will be added to vMix in offline mode and can't be used until the file is located manually by right clicking the input and selecting Change.

Recent Presets

Quickly open a recent preset by clicking the arrow button next to the Open button.