How to Disable Runaway UnistackSvcGroup Services?

I solved the problem by setting in the Registry the start value for these two fields from 3 (manual) to 4 (disable):

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\UnistoreSvc
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\UserDataSvc

The Unistore Services belong to the Windows store. Looks like the store installs App-Updates. In the store option you can turn off the automatic update.