1. the connection settings are saved automatically when GCC is closed, they are not save explicitely. Can't find a problem here, my settings are always saved.

2. in Backup and Restore only the sensor data are supported so far, works fine. Please tell me exactly where and when what crashes. Screenshots might help

3. I can save and append measurement data. Maybe you changed the sensors by adding/reomving cards or changing the measurment ranges? Then the data is not compatible and can't be appended.
If not, please give me more details.