This is happening on all our work related systems. So we don't get Push notification sounds for any new mails or work orders. Everytime we have to right click on Sound icon -> Open Volume Mixer -> Unmute System sounds. Then a new Cumulative Update gets installed, bam! all system sounds muted again. I asked Microsoft support but according to them, it is a non issue. What is going on? Our business relies on online ordering webpage and we do face delays if there is no audible notification. Any suggestions? I tried reinstalling Windows 1803 but no help. We have absolutely cleanest Windows systems with no extra apps or even office. Just use Edge for browser based notifications and Epson Printer driver for printing Receipts.