can not save session default...

Hi,
I am new to capture one and am having a little problem.
I have set up my images folders and within that I have a 'raw to process' folder and a 'processed tiffs' folder. The first I have set as my captures folder and the second as my processed folder. The first also contains the capture one settings folder. Each time I quit the programme an error message comes up saying 'couldn't save sesion default' and it gives me the option to save it where i choose. I have saved it to both the capture one settings folder within my capture folder and also to the general folder containg my capture and processed folders.
All the raw adjustments are still being saved but where do I need to save this default.session file both for it to be used and to stop the eroor message appearing.

Thanks.

Marc Wilson