You've probably worked out how to fix this by now. But if you get some sort of database corruption with the Litecoin Blockchain, you should enter the Litecoin
Data Directory and delete the relevant files, and then reopen Litecoin Core.
The Litecoin data directory on a Mac is located in
You should be able to access this directory by opening Finder and using the following command:
cmd + shift + g. And when it asks to the folder you want to enter, just copy and paste the Litecoin Data directory location provided above.
To delete the blockchain files, go inside the data directory, and delete the folder called
blocks. That should work...
If there is another error, please share it with us by copying over the debug.log file found in the Litecoin data directory.