After reinstalling the wallet part of the coins dsappeared

there was one problem. After updating the wallet to version 0.7, the network is not synchronized and the minted coins are generated and unconfirmed. After reinstalling the wallet, a substantial part of the coins have disappeared.
Tell me, please, how to fix it?

once in a while, your staked transaction is not accepted by the network as there was someone else just before you. So they stay unconfirmed, as if it never happened.
Or in your case minting stakes while not compleetly synced. Result is the same, they are invalid.

Hope this clearify your conception of ‘disapeared’ coins

Seem to have this same issue