Bitcoin Core 12.0 64bit Startup Error

[AnovaXT]

I'm getting the following error in the debug.log at startup. The splash windows shows it stuck at the "Activating best chain..." stage.

Code:

2016-03-22 11:29:31 UpdateTip: new best=00000000000000b9f7b4bfaee1287b3e51fd534cdb30f42c482dfff7f714f6d3  height=237053  log2_work=70.080714  tx=18132304  date=2013-05-20 12:10:02 progress=0.072438  cache=32.1MiB(25880tx)
2016-03-22 11:29:31 ERROR: CheckBlock(): hashMerkleRoot mismatch
2016-03-22 11:29:31 ERROR: ConnectTip(): ConnectBlock 00000000000000afe58811aea548dac4d6f4fd8c9c2b88836c84170ab52b03b8 failed

Are there any files I should delete/reset to get this resolved?

[achow101]

It looks like you have some file corruption here.

Go to the data directory and delete everything there except for the wallet.dat file. Backup the wallet.dat file to a safe place because that is the wallet and it contains everything you need to spend your Bitcoin. By deleting everything else, you will be doing a full resync which can take several hours depending on your computer and internet speed. It should fix your problem though.