If your drive is corrupted, you can’t predict how it will act… And it’s common for corrupted drives to be unrecognizable by computers. Corruption – Virus attacks, power outages, and software issues can all cause corruption.A bit of debris is enough for the connectors to fail. Broken cable or port – It’s possible that the problem is not with your hard drive, but with your cables or ports.While there are a multiple possible causes why Mac is not recognizing your Toshiba external hard drive, they usually only fall under 4 categories: Why Mac Is Not Recognizing Toshiba External Hard Drive More importantly, we guide you step-by-step through recovering the data on your drive with tools you can download on your Mac. So stop using it until you finish reading this article.īelow are all the possible reasons why your drive isn’t showing, as well as the fixes you can try. And if you continue to use a problematic drive, the damage often gets worse. If your Toshiba external hard drive is not showing up on Mac, it’s possible that you’re on your way to data loss.