As the Table browser is now closed down for editing data in D3FO, and a Production environment does not provide Visual Studio or RDP access, I only know one way of fixing this, until Microsoft comes up with a fix.
Use the Entity "Master Planning Parameters" to export the paramaters to Excel.
Set the value of the field AREALLPLANNINGPROCESSESDISABLED to 'No'.

Save File.
When importing use the Import option 'Re-import'.

In the Re-import settings, set 'Yes' in the Field 'Ignore errors' and click Import.

The Planning processes are now enabled and the remaining Master Planning parameters can be setup