The first step of wallet repair to make sure you are on the the lastest version of NavCoin Core. Read this guide to update your wallet to the latest version.
If your wallet is out of sync, either wait, and allow it to sync naturally, or follow this guide to bootstrap your wallet’s blockchain.
Finally in the toolbar of the NavCoin Core wallet, under File
there is a Repair Wallet
option. Click this an the software will attempt to repair your wallet.
Visit the NavCoin Community Discord server and ask for help in the #navcoin-support
channel: https://discord.gg/y4Vu9jw