Q. Can I recover my personal data that's missing from Libby?

The best way to guard against this happening is to create a passkey.

See "Backing up your data in Libby"

If you want to have the Libby app installed on a couple of different devices to have the apps synchronized, you should use a passkey or setup code for the second device installation. Thereafter, if you have to un-install the app on one device, when you re-install it you can again use a setup code to link it to the app on the other device and get them synchronized.

These help articles may also help:

Recovering card history

Reading history

Exporting and sharing tags