After the 990 update my device stopped saving daily recordings (in my case both FIT & GPX) and the data is lost.
On startup the next day the device does recognize the setting as it clears the current. But the cupboard is bare, nothing is saved and the Activity & GPX - Archive folders remain empty.
If you have this issue it is possible to revert back to 980 if you have a copy which will restore the proper functionality. But by downgrading you will also have to reconfigure all your personal settings. And be careful to delete any 990 gupdate.gcd that Express may surreptitiously deposit in the Garmin folder without your permission whenever you subsequently connect.
It is also possible to recover the lost track data in 990 if you also log RINEX, but with most common tools you will have to go through the post processing to obtain the corrected data.