Best is just to remove the peers.dat file from your installation directory (should be in the same folder as where your wallet.dat is located) and install the new Dash wallet. The wallet will create a new peers.dat file with new connections, when you start it again. This should help with the syncing. With windows there is a zip file that you can download and where you can extract the dash-qt.exe from and simply replace the old dash-qt.exe. With MAC there should be something similiar to updating your dash wallet. Edit : looks like you will download a .dmg file for OSX, which means installation is a bit different (I'm not a MAC user). Just follow installation guide here : https://docs.dash.org/en/stable/wallets/dashcore/installation-macos.html The update from v0.12.2 to v0.12.3 should not effect your wallet.dat (you have a backup anyways). If you still have problems syncing, then try removing the following files from your Dash installation directory when wallet is closed : mncache.dat fee_estimates.dat governance.dat mnpayments.dat netfulfilled.dat banlist.dat peers.dat These files are safe to delete (they get re-created at wallet restart), do NOT delete your wallet.dat Restart wallet.