Error 1603 for every install

[Sheridan]

On one of our 2012 R2 servers we can't install anything, every installer we've tried simply fails with the even viewer showing 'Installation success or error status: 1603'

 

Verbose logging doesn't show much more apart from the line:

MSI © (A4:F0) [10:38:10:684]: Back from server. Return value: 1603

 

I've tried a different account, restarting the Installer service, re-registering the installer service and checked all the permissions to the program files folders but everything seems ok?

 

Of course its a heavily used server so a full reboot is the last resort!

[mrwoberts]

An out of hours reboot was my first thought, because making other changes may well be digging a deeper hole.