macOS Monterey USB Bug Fixes

When a USB drive suddenly stops working on a Mac, it is frustrating – and for a while, macOS Monterey made it more common than it should have been. A well-documented bug caused USB and Thunderbolt devices to drop out unexpectedly, particularly when connected through hubs. Whether you are chasing that specific issue or just trying to get a stubborn drive to mount, this guide walks through the fixes for USB problems on macOS, from the simplest checks to the last-resort options.

The macOS Monterey USB bug

Shortly after macOS Monterey launched, many users reported that their USB and Thunderbolt peripherals – drives, hubs, docks and accessories – were randomly disconnecting and reconnecting, or failing to be recognised at all. The problem was especially noticeable on Macs using USB hubs and docking stations, and it affected both Intel and Apple Silicon machines. It was a software issue rather than a fault with the drives themselves, and Apple addressed it in subsequent Monterey updates. So if you are running an older version of Monterey and seeing these symptoms, the single most important step is to update macOS to the latest version – that alone resolved the bug for most people.

First, rule out the simple things

Before diving into anything technical, eliminate the common culprits – they account for most USB problems on any computer. Try a different cable, as faulty or charge-only cables are a frequent cause. Plug the drive into a different port, ideally directly into the Mac rather than through a hub or dock, which are the very things the Monterey bug affected. Avoid unpowered USB hubs for power-hungry drives, which may not get enough current. And simply restart the Mac – a reboot clears a surprising number of temporary glitches. If the drive works after these steps, you have found your answer without any deeper troubleshooting.

Step-by-step fixes

Update macOS

Since the Monterey USB issue was fixed in updates, keeping macOS current is the first real fix to try. Go to System Preferences (or System Settings) → Software Update and install anything available. Apple has patched several USB-related bugs over the years, so an up-to-date system avoids many known problems.

Reset the NVRAM (Intel Macs)

On Intel-based Macs, resetting the NVRAM can clear port and peripheral glitches. Shut down, then power on and immediately hold Option + Command + P + R for about 20 seconds before releasing. Apple Silicon Macs handle this automatically and have no manual NVRAM reset – a simple restart does the equivalent.

Reset the SMC (Intel Macs)

Also on Intel Macs, the System Management Controller governs power and ports, and resetting it can fix hardware-level issues. The exact key combination depends on the model, so check Apple’s instructions for yours. Again, Apple Silicon Macs manage this internally, so a full shutdown and restart is all that is needed.

Run Disk Utility First Aid

If the drive is detected but behaving oddly – mounting slowly, showing errors or not opening – open Disk Utility (Applications → Utilities), select the drive, and click First Aid. This checks the drive for errors and repairs many minor filesystem problems that stop a drive working properly.

Check System Information

To see whether the Mac detects the drive at all, open the Apple menu → About This Mac → System Report (or System Information) and look under USB. If the drive appears there but not on the desktop, the issue is likely with formatting or mounting rather than the connection; if it does not appear at all, focus on the cable, port and the drive itself.

When the drive itself is the problem

If you have tried everything and the drive still will not work – and especially if it fails on more than one computer – the drive itself may be at fault. Test it on another Mac or a PC to confirm: if it fails everywhere, the drive is the issue, not your Mac. A drive that is physically damaged, worn out or simply faulty may be beyond repair. This is exactly why keeping a backup of important files matters – so a failed drive is an inconvenience rather than a disaster. Cheap, low-grade drives fail far more often than quality ones, which is a good reason to buy from a reputable supplier in the first place.

Reformatting a USB drive on Mac

As a last resort, reformatting can revive a drive with filesystem corruption – but it erases everything on it, so recover or back up any data you can first. In Disk Utility, select the drive, click Erase, choose a format (exFAT is a good choice if you use the drive on both Mac and Windows), give it a name, and confirm. Once reformatted, a healthy drive should mount and work normally again. If it still fails after formatting, the drive has likely reached the end of its life.

Preventing USB problems on your Mac

Many USB headaches can be avoided with a few good habits. Keep macOS up to date, since Apple regularly patches USB and peripheral bugs. Always eject drives safely before unplugging – drag the drive to the Bin or use the eject arrow in Finder – so the system finishes writing and the filesystem stays intact. Use good-quality cables and, where possible, a direct connection rather than an unpowered hub, especially for larger drives. Format drives with exFAT if you move them between Mac and Windows, to avoid compatibility issues. And look after the drive itself – our guide to caring for your USB memory stick has more. Above all, keep backups of anything important, so no single glitch or failure ever costs you your files. A little prevention makes the occasional USB gremlin a minor annoyance rather than a crisis.

A note on connectors and compatibility

Some “USB problems” on modern Macs are really compatibility mismatches rather than faults. Recent Macs favour USB-C ports, so a traditional USB-A drive needs an adapter or a hub – and a poor-quality adapter can itself be the source of dropouts. If you regularly use a Mac, a drive with a USB-C connector, or a dual-connector drive with both USB-A and USB-C, sidesteps the issue entirely and plugs in directly. It is also worth remembering that the connection runs at the speed of the slowest link, so pairing an old drive with a new Mac may feel sluggish even when everything is working. If you are choosing drives for a Mac-heavy audience, our guide to USB versions and connectors explains which to pick, and a little thought about connectors up front prevents a lot of “it won’t connect” confusion later.

A few more advanced checks

If the basics have not solved it, a handful of deeper checks are worth a try. Boot into Safe Mode (the method differs between Intel and Apple Silicon Macs) and see whether the drive works there – if it does, a login item or third-party extension may be interfering with USB in normal mode. Check for conflicting third-party drivers or utilities, such as older disk or antivirus tools, which have been known to disrupt USB behaviour after a macOS upgrade. In Disk Utility, use the View menu to “Show All Devices” so you can see the physical drive as well as its volumes – sometimes a drive appears at the device level but its volume fails to mount, which points to a formatting problem you can repair or reformat away. And if only one port misbehaves while others work, you may simply have a faulty port rather than a software issue. Working through these one at a time helps you pinpoint whether the problem lies with macOS, a piece of software, the port, or the drive – which is exactly what you need to know before deciding what to do next.

When to seek professional help

Most USB issues are well within reach of the steps above, but there are times to call in help. If the drive holds irreplaceable data that you cannot back up and it will not mount anywhere, stop experimenting – repeated attempts and especially reformatting can make professional recovery harder or impossible. A specialist data-recovery service can sometimes retrieve files from a drive that a computer can no longer read, though it comes at a cost that only you can judge against the value of the data. Likewise, if you suspect a hardware fault with the Mac itself – a dead port, or problems across many devices – an Apple-authorised technician can diagnose it properly. The guiding principle is simple: the more important the data and the less sure you are of the cause, the sooner it is worth pausing rather than pressing on. For everyday drives with backed-up content, though, the checklist in this guide will resolve the vast majority of problems yourself, quickly and for free.

Help & Support

Frequently Asked Questions

What was the macOS Monterey USB bug?

After macOS Monterey launched, many users found their USB and Thunderbolt devices – drives, hubs, docks and accessories – randomly disconnecting or not being recognised, especially through hubs and docking stations. It was a software bug affecting both Intel and Apple Silicon Macs, and Apple fixed it in later Monterey updates.

How do I fix USB devices disconnecting on Monterey?

First, update macOS to the latest version, since the bug was patched in updates. Then connect the device directly to the Mac rather than through a hub or dock, try a different cable and port, and restart the Mac. These steps resolve the issue for most people.

Why is my USB drive not showing up on my Mac?

Common causes are a faulty or charge-only cable, a hub not supplying enough power, an out-of-date macOS, or a formatting or filesystem problem. Try a different cable and a direct port, restart, update macOS, and check whether the drive appears in System Information and Disk Utility.

How do I run First Aid on a USB drive?

Open Disk Utility from Applications → Utilities, select the USB drive in the sidebar, and click First Aid. It checks the drive for errors and repairs many minor filesystem problems that stop a drive mounting or opening correctly.

How do I reformat a USB drive on a Mac?

Reformatting erases everything, so back up first. In Disk Utility, select the drive, click Erase, choose a format (exFAT works on both Mac and Windows), name it and confirm. A healthy drive should then mount and work normally; if it still fails, it may have reached the end of its life.

How can I avoid USB problems on a Mac?

Keep macOS updated, always eject drives safely, use good-quality cables and a direct connection rather than an unpowered hub, format with exFAT for cross-platform use, and keep backups. Choosing quality drives and, for modern Macs, USB-C or dual-connector drives also helps avoid issues.

Conclusion

USB problems on a Mac are almost always fixable, and usually with the simplest steps. If you are chasing the macOS Monterey disconnection bug, updating macOS and connecting devices directly rather than through a hub is the key fix. For any stubborn drive, work methodically through the checks – cable, port, restart, update, NVRAM or SMC reset, Disk Utility First Aid – before considering that the drive itself may be at fault. Keep macOS current, eject drives safely, use quality drives and cables, and always keep a backup, and you will avoid most trouble in the first place. If you are looking for reliable branded USB drives that play nicely with Macs and PCs alike, our team is happy to help.