Backup Exec 16 rev.1142 will not start

Hi, my Backup Exec 16 will not start (has being running flawlessly since installation). Pop's up with "Backup Exec has stopped working". Details.: Event Name - CLR20r3 - no help checking online for a solution.  

Application Error Message in the Windows event log.:

Faulting application name: BackupExec.exe, version: 16.0.1142.0, time stamp: 0x57f0f61d
Faulting module name: KERNELBASE.dll, version: 6.3.9600.19671, time stamp: 0x5e673d0b
Exception code: 0xe0434352
Fault offset: 0x00000000000088dc
Faulting process id: 0x1b84
Faulting application start time: 0x01d63f00937f795a
Faulting application path: C:\Program Files\Veritas\Backup Exec\BackupExec.exe
Faulting module path: C:\Windows\system32\KERNELBASE.dll
Report Id: d167a3bd-aaf3-11ea-80fb-288023b04a8b
Faulting package full name:
Faulting package-relative application ID:

.NET Runtime error in the Windows event log.:

Application: BackupExec.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.Reflection.AmbiguousMatchException
at System.RuntimeType.GetMethodImpl(System.String, System.Reflection.BindingFlags, System.Reflection.Binder, System.Reflection.CallingConventions, System.Type[], System.Reflection.ParameterModifier[])
at System.Type.GetMethod(System.String, System.Reflection.BindingFlags)
at BackupExec.ThemeManager..cctor()

Exception Info: System.TypeInitializationException
at BackupExec.ThemeManager.ChangeTheme(System.String, System.String)
at BackupExec.App..ctor()
at BackupExec.App.Main()

Have tried server restart, and checked that all 7 Backup Exec services are running.

Hope there are someone out there that might help me with a soulution to my problem ;-)

Rgds. Stein