Accessing Environment Variables in a Scheduled Task

You do not need a machine reboot. You should terminate Taskeng.exe and the next time scheduled task is run it will get an updated environment.

I thought that you could reference environment variables from the Task Scheduler, but having just tried, it doesn't look like you can.

The one exception appears to be %PATH% so would it be possible to add your MyAppPath value to the %PATH% collection on each machine, then then just call MyApp.exe from the task scheduler, where the machine will be able to resolve the fully-qualified path as required?