Ok so forget Wine, I've downloaded Windows 10 on Parallels, and the latest version of the windows Hyper wallet. Unfortunately that's not working either. It keeps saying that it's already running, when its not. Going back to the Mac wallet that I had previously, I'm very confused about what it is I should back up - everything on this forum says I should back up the wallet.dat file, but I've never had a wallet.dat file in the Hyper directory - just the blk0001.dat and blkindex.dat. Am I missing something here? Also, when you say 're-download the blockchain' which file are you talking about? I tried downloading the bootstrap but all that's there is a bootstrap.dat, which when I copy it into the folder doesn't help (I still get the 'Error loading blkindex.dat' problem). Sorry guys I've been at this for nearly a day now but still no luck. Any help would be much appreciated!