Kinda had forgotten what time it takes to... install the thing from scratch.
So, I was able to start DCS Server, using our standard mission on the Causasus map. It ran.
And when finished, to discover... maps... install them. One by one. Oh dear.
DCS_updater.exe install SINAIMAP_terrain - done
Currently installing these in a batch file, one by one, one after the other, hoping no errors will occur... lol
DCS_updater.exe install PERSIANGULF_terrain
DCS_UPDATER.EXE install MARIANAISLANDS_terrain
DCS_Updater.exe install THECHANNEL_terrain
DCS_updater.exe install NEVADA_terrain
DCS_updater.exe install SYRIA_terrain
DCS_updater.exe install NORMANDY_terrain
Tomorrow I will have a look at the result.