If you're getting the following NW.js screen on startup, then follow the steps below in order to resolve this:

 Ensure that the shortcut you're using isn't a dead link. Try running the executable directly:

Altaro VM Backup: C:\Program Files\Altaro\Altaro Backup\ManagementTools\Altaro.ManagementConsole.exe
Altaro Offsite Server: C:\Program Files\Altaro\Altaro Backup\ManagementTools\Altaro.OffsiteServer.ManagementConsole.exe

 If you are running Windows Server 2019 and you have been logged on to the machine for more than seven days, the %TEMP% location is cleaned automatically, which can cause this issue. More information on this here. A log out and log in from the machine will resolve the issue.

If opening the executable directly still presents the same screen, ensure that you have ample free space on the C: (or where Altaro is installed)

Lastly, check whether the Windows tmp location is accessible. You can open 'Run' and type in %tmp%. If that presents an error, it's also what causing Altaro inability to run - once that is resolved attempt to run Altaro again.