cd in the folder containing the executable (windows or ubuntu) and
darkcoin-qt -reindex
darkcoind -reindex
Or delete everything in the darkcoin folder
except the wallet.datIt stuck on some block number again!
Some masternodes are destroying whole network. There are so many block chains.
If you have the latest wallet, start it with the -reindex option.
you can follow then the debug.log file, to have something scrolling on you screen and pretending to work, if you work in IT.