It’s a scenario that can send a shiver down any Mac user’s spine: you plug in your trusty external hard drive, ready to back up precious photos, transfer large files, or simply access your extended storage, and… nothing. Your Mac, usually so intuitive, seems to have suddenly gone deaf to your drive’s pleas for attention. This isn't just an inconvenience; for many, it can feel like a digital brick wall, especially when Time Machine backups are involved.
I've been digging into this issue, and it seems to be a recurring headache for some Mac users, particularly those with newer M2 MacBook Air models. One user, "One_Andy" on the Apple Community forums, shared a story that resonated with many. After experiencing their M2 MacBook Air M2 failing to detect external hard drives, they found a resolution with macOS 15.3. The problem, they theorized, was a software glitch under macOS 15.2 that caused the motherboard to under-supply power, essentially making it blind to connected drives. It’s a relief when a software update can fix such a fundamental issue, but it also leaves a lingering question: will future updates bring back the problem?
This isn't an isolated incident. Other users have reported similar experiences. One user with a MacBook Air (M2, 2022, macOS Monterey 12.7.2) found their Mac suddenly stopped recognizing both Seagate and Western Digital drives after about a year of use. They’d tried all the usual suspects: checking cables and ports, testing the drives on an older Mac (where they worked perfectly), restarting, safe mode, and updating the OS. Even running Disk Utility First Aid on the drives offered only a temporary fix. Oddly, a SanDisk thumb drive continued to be recognized, leading to speculation about why some devices are favored over others.
Another user with a 2023 M2 MacBook Air encountered the same issue, with Disk Utility failing to see LaCie and Seagate drives connected via a hub. They’d also gone through the standard troubleshooting steps, including checking preferences for showing external drives and allowing connections, but to no avail. The drives themselves were confirmed to be working fine on older Macs.
What’s particularly concerning is the potential impact on data backup strategies. When your primary backup solution, like Time Machine, becomes unusable due to an unrecognized external drive, it’s a significant worry. The frustration is compounded when the drives themselves are proven to be functional on other machines.
While software updates like the one that helped One_Andy are often the key, the underlying cause can sometimes be more complex. It might involve how the Mac communicates with external storage devices, power delivery issues, or even specific driver incompatibilities. For those still struggling, checking System Information (under the Apple menu > About This Mac > System Report) can sometimes offer clues, showing if the USB bus is detecting anything connected, even if it’s not properly identifying the drive.
It’s a reminder that even with advanced technology, sometimes the simplest connections can be the most perplexing. The good news is that community forums and software updates often pave the way for solutions, bringing those essential external drives back into the fold.
