electron-builder: NSIS Autoupdater Fails to update

• Version: 8.6.0

• Target: Win64 Nsis

I use Github for updates and download works but on install it fails. My updater code is (imports are simplified):

const {autoUpdater} = require('electron-auto-updater')
function update () {
  setTimeout(function() {autoUpdater.checkForUpdates()}, 30000);
  autoUpdater.on('checking-for-update', function() {
    about.webContents.send('Updater' , {status:'checking'});
    tray.displayBalloon({
      title: 'Autoupdater',
      content: 'Es wird nach Updates geprüft!'
    })
  });

  autoUpdater.on("error", (err) => {
    about.webContents.send('Updater' , {status:'error'});
    console.log(err)
    crashInit()
    tray.displayBalloon({
      title: 'Autoupdater',
      content: 'Ein Fehler ist aufgetreten!'
    })
    //process.crash()
  })

  autoUpdater.on('update-available', function() {
    about.webContents.send('Updater' , {status:'update'});
      tray.displayBalloon({
        title: 'Autoupdater',
        content: 'Es gibt ein Update!'
      })
  });

  autoUpdater.on('update-not-available', function() {
    about.webContents.send('Updater' , {status:'no-update'});
    tray.displayBalloon({
      title: 'Autoupdater',
      content: 'Es gibt kein Update!'
    })
  });


  autoUpdater.on('update-downloaded', function (event, releaseNotes, releaseName, releaseDate, updateUrl, quitAndUpdate) {
    var index = dialog.showMessageBox({
      type: 'info',
      buttons: ['Restart', 'Later'],
      title: "Lornsenschule Vertretungsplan",
      message: ('The new version has been downloaded. Please restart the application to apply the updates.'),
      detail: releaseName + "\n\n" + releaseNotes
    });

    if (index === 1) {
      return;
    }

    quitAndUpdate()
  });
}

Following errorLog comes after starting the install:

Unhandled rejection Error: spawn UNKNOWN
    at exports._errnoException (util.js:1026:11)
    at ChildProcess.spawn (internal/child_process.js:313:11)
    at exports.spawn (child_process.js:392:9)
    at NsisUpdater.install (C:\Program Files\Lornsenschule Vertretungsplan\1.0                                                                                                                    .0\resources\app\node_modules\electron-auto-updater\out\nsis-auto-updater\src\                                                                                                                    NsisUpdater.js:194:61)
    at NsisUpdater.quitAndInstall (C:\Program Files\Lornsenschule Vertretungsp                                                                                                                    lan\1.0.0\resources\app\node_modules\electron-auto-updater\out\nsis-auto-updat                                                                                                                    er\src\NsisUpdater.js:178:18)
    at C:\Program Files\Lornsenschule Vertretungsplan\1.0.0\resources\app\node                                                                                                                    _modules\electron-auto-updater\out\nsis-auto-updater\src\NsisUpdater.js:158:32
    at NsisUpdater.<anonymous> (C:\Program Files\Lornsenschule Vertretungsplan                                                                                                                    \1.0.0\resources\app\main.js:81:5)
    at emitMany (events.js:127:13)
    at NsisUpdater.emit (events.js:201:7)
    at C:\Program Files\Lornsenschule Vertretungsplan\1.0.0\resources\app\node                                                                                                                    _modules\electron-auto-updater\out\nsis-auto-updater\src\NsisUpdater.js:157:28
From previous event:
    at C:\Program Files\Lornsenschule Vertretungsplan\1.0.0\resources\app\node                                                                                                                    _modules\electron-auto-updater\out\nsis-auto-updater\src\NsisUpdater.js:154:20
    at next (<anonymous>)
    at runCallback (timers.js:574:20)
    at tryOnImmediate (timers.js:554:5)
    at processImmediate [as _immediateCallback] (timers.js:533:5)
From previous event:
    at NsisUpdater.doCheckForUpdates (C:\Program Files\Lornsenschule Vertretun                                                                                                                    gsplan\1.0.0\resources\app\node_modules\electron-auto-updater\out\nsis-auto-up                                                                                                                    dater\src\NsisUpdater.js:166:11)
    at C:\Program Files\Lornsenschule Vertretungsplan\1.0.0\resources\app\node                                                                                                                    _modules\electron-auto-updater\out\nsis-auto-updater\src\NsisUpdater.js:117:36
    at next (<anonymous>)
From previous event:
    at NsisUpdater.checkForUpdates (C:\Program Files\Lornsenschule Vertretungs                                                                                                                    plan\1.0.0\resources\app\node_modules\electron-auto-updater\out\nsis-auto-upda                                                                                                                    ter\src\NsisUpdater.js:122:11)
    at Timeout._onTimeout (C:\Program Files\Lornsenschule Vertretungsplan\1.0.                                                                                                                    0\resources\app\main.js:30:38)
    at tryOnTimeout (timers.js:232:11)
    at Timer.listOnTimeout (timers.js:202:5)