Hi since around October whenever I open lightroom it updates the catalog then works fine but when I close it it loses everything I have done - imports/edits etc.
If Lightroom updates the catalog each time you open it, then your old catalog is set as the catalog to open in the preferences. As a result, you upgrade the old catalog again each time, and so you won't see anything you did the last time you worked in Lightroom, because that will be in the previously upgraded copy...
I have checked and the catalog set to open was the last used so that is not the problem - I did try setting so it would open the V12 catalog specifically but it still tried to upgrade the V10 version. When I try and create a new catalog it tells me it cannot open it as it does not exist.
I will try chat and see if that will solve the issue.
I spent over an hour on chat and remote access with Adobe support who couldn't solve the problem either! Their final suggestion was to reinstall Lightroom which has been sucessful in solving the problem,