@Ajax

If you are playing single player there is an unfortunate occurrence that could happen if you are playing singleplayer, if when you click launch game, while the mod is still installing (displayed in the bottom right of screen) it will launch the game without the mod installed yet.
when the game loads up, as the mod is not installed, the mod items are not loaded, then when you exit, an auto save occurs with the parts not there (this is easily fixable so don't panic)

If you restore to the save file before the issue it will be corrected

Some of us in the sponsored mod group have requested ark add a pop up when launching a single-player game if a mod is still installing when clicked as this very easily done without a pop-up. :)

Thank you for help. Unfortunately I dont know how to restore the game to a previous save. I bought the game months ago and still find it baffleing. Stand under 5 floors furniture etc etc and it rains on you, Stand under one ramp and no rain comes through. I might start again when the official release comes out. Hopefully these bugs will be fixed. Bit of a rip-off if it still dousn't work then.
Thanks again for the advice.