This will solve problems while synchronizing the blockchain, or if you are receiving errors while starting the wallet.
Make sure you are up to date with the latest wallet software version. Download the latest version here.
Close your wallet before going to Step 2
Navigate to the XBY wallet data directory.
The default path is C:\Users\your_windows_username\AppData\Roaming\xtrabytes
Or do the following:
Hold the windows button and press R
In the box, write %appdata% then press enter
Go to Roaming
Go to Xtrabytes
Select everything except wallet.dat and delete them.
Do not delete the wallet.dat file. This is what holds your XBY coins.
Restart your wallet and the sync process will begin automatically.