In my comment in this thread I’ve explained how you can backup and restore an Engine Prime collection database
On the support TeamViewer sessions I had, I’ve seen a lot of Prime 4 users swtich between “Computer mode” and “Stand alone mode” without
- Quiting Engine Prime (and for Windows users: Quit is Alt+F4, or choosing “quit” from the file menu, not closing a window)
- Unmounting (ejecting) the Prime 4 internal drive from their computer.
Both of these steps needs to been performed in that order before you switch the Prime 4 to Stand alone (or before you power it off). Failing will lead to database corruption.