How to: Start an application without a lasting installation

From 3.3.0 the starter can run an application from a USB stick or another removable drive without leaving it installed on the PC. It sets up what the application needs, stays in the notification area while the application runs, and removes what it set up when the session ends. Use it for a demonstration, the tools of a service technician, or a PC on which nothing may stay installed.

Prerequisites

A project file of format 2 and the starter 3.3.0 or later.
The starter, its project file and the delivery folder on the stick, with source relative to the starter (for example "source": "Kasse"), so the stick works under any drive letter.
No administrator rights: a session writes only to the user's profile and below HKEY_CURRENT_USER, as every start does.

Set up the session

Add the session section to the project file:
```
"session": { "mode": "removable", "graceSeconds": 60, "countdownSeconds": 30, "remindMinutes": [5, 15, 60] }
```
With mode removable, a start from a removable drive is a session, and a start of the same project from a hard disk or a share installs for good. With always, every start is a session. The other values are the defaults; the project file reference lists their limits.
Copy the starter, the project file and the delivery folder to the stick.
On the PC, start the application with the starter on the stick.

What happens in a session

Moment	What the starter does
Start	Installs what the application needs to run: its files, the COM registration for the user and the trusted location. It creates no shortcuts, file types or entry under Windows „Apps“. It records the session in `%LOCALAPPDATA%\WKL\Sessions\<product>.json`.
While the application runs	Shows its icon in the notification area, with the commands Open application, End and clean up and Settings.
The application is closed	A notice offers Open again and Clean up and counts down `graceSeconds`. Without an answer, the starter cleans up.
The stick is removed	A notice asks whether to Clean up, to Wait, or to Snooze for one of the times of `remindMinutes`. It counts down `countdownSeconds` and then cleans up as if Clean up had been chosen.
Cleanup	Removes what the session installed, as `/uninstall` does. Components that another application of the user still uses stay. If the application is still open, the cleanup waits until it is closed; the starter never closes it. Then the starter ends.

The notice appears at the bottom right of the screen without taking the keyboard focus, so typing in the application cannot answer it by accident. Closing the notice is no answer: the countdown goes on, and a click on the icon shows the notice again. Wait asks no more until the stick is back or the application is closed.

Expected result

After the session, /list shows nothing of the product, and the registry holds no entry of it below HKEY_CURRENT_USER. Of %LOCALAPPDATA%\WKL\<product>, only the log folder Logs stays, with the lines of the session.

Remarks

Installed before: a product that a normal start had installed on the PC before the session stays installed; the session does not remove it.
Interrupted session: if Windows shuts down or the starter ends during a session, the next start of any starter of the user cleans the session up first. If the application still holds its files at that moment, the cleanup waits for the next start.
Second start: starting the same application again during a session opens it within the session; nothing is installed a second time.
External hard disk: Windows reports an external hard disk on USB as a fixed drive. For a delivery on one, set mode to always; its removal is then not watched, and the session ends when the application is closed.
Starter without the stick: when started from a removable drive or a share, Windows loads the starter completely into memory, so it keeps running after the stick is removed.
beforeUninstall: the programs of the project with when beforeUninstall do not run at the end of a session; the project file may be gone with the stick.