Hi. I've got an external hard drive (Toshiba) that I've been using for storage for maybe two years now. It's been working perfectly and I've got it on HFS+. As of today I've been unable to use it with my iMac (2015, 27"). I cannot browse it as it doesn't show up in Finder etc, although I can see it in Disk Utility. Trying to repair it results in errors, saying it's unable to control it. "Invalid key length" and "invalid post count" (might be incorrect, translating from Swedish). The strange thing, I suppose, is that the hard drive is working. I've got a Windows laptop with Paragon installed, and I can still browse it from within the Windows computer. I don't have another Mac at home, unfortunately, and so I'm unable to try and pair it with another computer running OS X. Any help with regards to what may be the problem is greatly appreciated. And if there is an alternative to Disk Utility that *could* help me out, please do hook me up. Regards.