Which version are you running of Dash ? Make sure you are running latest version 0.14.0.2
If you still have problems with latest version, then first check your debug.log (it may mention you need a -reindex)
Options available :
Option 1 : Try a -reindex to see if that gets your wallet started
Option 2 : Make a backup of the evodb folder --> rename that backup to nonevodb --> remove the orginal evodb folder --> start wallet with -reindex
* if that works and your wallet starts normally, you can then delete your nonevodb backup folder
Option 3 : Delete your blockchain and sync from scratch (you can download a bootstrap here :
https://github.com/UdjinM6/dash-bootstrap)
* when bootstrap is finished it will rename itself to "bootstrap.dat.old" and you can then delete it