Thanks Mark. Do you also have a model.200 folder with this in the .cfg?

[models]
normal=..\model\x732
interior=..\model\x737_interior

I've been reinstalling the same csp732_1000 file from my hard drive to try fixing a few issues. I think it's time to delete that one and d'load a new one!

Update: downloaded/installed the 737 again, and the installation looked good (model=200 in the .cfg).

Then I ran ACE, deleted the unwanted liveries, saved the remaning liveries as "flight deck only" which correctly saved as

model=

But when I uncheck "flight deck only" for a livery it saves the .cfg with

model=100  :-?