Go through the following list for plausible reasons behind external storage drive not mounting on macOS Catalina: You would need to analyze the root-cause to fix the ‘drive not-mounting’ issue. It can be due to other factors that prevent your macOS from reading the drive normally. The trouble may not always be with the new operating system that you’ve recently installed. Thanks.”Įxternal storage drive not mounting on macOS is not a new issue. Please suggest if there’s a way to mount my drive and access the data. I’ve stored my treasured family photos and videos on the drive, which I don’t want to lose. When I connect my external hard drive to the Mac, the drive is not mounting. “Hi, after upgrading my Mac to Apple’s latest macOS Catalina 10.15, I’m facing a problem. : External Hard Drive Not Mounting on macOS Catalina 10.15