THIS DOESN'T APPEAR TO WORK IN 21H1.  TO DISABLE NOTIFICATIONS, USE GROUP POLICY:


COMPUTER CONFIGURATION - ADMINISTRATIVE TEMPLATES - WINDOWS COMPONENTS - WINDOWS SECURITY - NOTIFICATIONS


CHANGE "HIDE ALL NOTIFICATIONS" TO "ENABLED" AND REBOOT

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You can disable taskbar balloon notifications by doing the following steps:

  1. Click Start, click Run, type regedit, and then press ENTER
  2. Locate the following subkey:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced

  1. Right-click the right side pane, create a new DWORD value, and then name it EnableBalloonTips.
  2. Double-click EnableBalloonTips, and then give it a value of 0.
  3. Close Registry Editor
  4. Log off Windows, and then log back on.

Source: How do I disable balloon tips in the notification area in Windows XP or Vista?


Or you can run:

reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced" /v "EnableBalloonTips" /t REG_DWORD /d 0 /f

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You can either change this setting directly...

  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile  set REG_DWORD value DisableNotifications to 1
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\PrivateProfile   set REG_DWORD value DisableNotifications to 1
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\PublicProfile    set REG_DWORD value DisableNotifications to 1

...or set it as policy...:

  • In HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\WindowsFirewall\DomainProfile set REG_DWORD value DisableNotifications to 1
  • In HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\WindowsFirewall\PrivateProfile set REG_DWORD value DisableNotifications to 1
  • In HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\WindowsFirewall\PublicProfile set REG_DWORD value DisableNotifications to 1