It might happen that after deleting and resyncing / rescanning the blockchain to fix the "assertion Failed"- issue that you end up with the error described in the title of this guide.
these are the steps to fix this issue.
1. before proceeding to step 2, make sure you have an own backup of your wallet.dat file (located in the %appdata% > xfuel-folder). Also doublecheck if you have the private keys for all your addresses within that wallet. If so, move to step 2.
2. Make sure that no instance of the wallet is running in the background.
3. open a CMD-screen and navigate to the folder that contains the xfuel.exe file
4. type following command : "xfuel.exe -salvagewallet
This might take a while for the wallet to recover, but after this the wallet should open again with your balance.
note: in case you cannot see your receive address(es) in the receive tab use the debug console to add your addresses in the wallet. Allthough this action might return an error, you'll notice that your address(es) will be visible now.
contact our support team in case the steps above did not solve the problem.