How to see other drives connected to your Mac
Other volumes on your Mac appear in the Finder sidebar under "Locations" — usually labeled by their name or "Untitled" if they have no name yet. External drives, USB flash drives, SD cards, and secondary internal drives all show up in the same place. If you don't see a drive you know is connected, it may not be mounted, or Finder may be hiding it from the sidebar.
The fastest way to see everything connected is to open Finder, click the Finder menu at the top left, select Preferences, then go to the Sidebar tab. Check the boxes next to "External disks" and "Hard disks" — this forces all connected volumes to appear, even if they're not formatted for Mac. You can also press Command+Shift+C to jump straight to the Computer view, which shows every mounted volume in one window.
If a drive is plugged in but doesn't appear anywhere, it may need to be mounted first. Some external drives go to sleep or require a specific app to unlock. Restarting your Mac often wakes a sleeping drive. If the drive still doesn't show up, it may not be formatted in a way your Mac recognizes, or it may need repair — both are covered in later sections.
Key Takeaways
- External drives and secondary internal volumes appear in the Finder sidebar under Locations, and you can force them to show by enabling "External disks" in Finder Preferences.
- A connected drive that doesn't appear may be asleep, unmounted, or formatted in a way your Mac doesn't recognize without additional software.
- You can read files from most volumes without doing anything — just click the drive name in Finder and browse like a folder.
- Writing to an external drive formatted for Windows requires third-party software on newer Macs, because macOS can only read NTFS by default.
- Ejecting a drive safely before unplugging prevents data loss and is done by right-clicking the drive name and selecting Eject.
Reading files from an external drive or secondary volume
Once a drive appears in Finder, you can open it like any folder — click its name in the sidebar, and the contents appear in the main window. You can copy files from the external drive to your Mac, move them around, or open them directly from the drive. This works the same way whether the drive is formatted for Mac, Windows, or Linux, as long as your Mac recognizes the format.
If you want to keep files on the external drive permanently rather than copy them to your Mac, you can work directly from it. Drag files into folders on the drive, delete things you no longer need, and organize it like you would your Mac's internal drive. The speed depends on the connection type — USB 3 drives are much faster than USB 2, and Thunderbolt drives are faster still.
Some external drives come with their own software or require a password to access. If a drive asks for a password when you click it, enter the password the drive's owner gave you. If you forgot the password, you'll need to erase the drive and start over — there's no way to bypass it.
Writing to drives formatted for Windows
A drive formatted as NTFS (the Windows standard) will appear in Finder and you can read files from it, but you cannot write new files to it or edit files already on it. macOS includes read-only support for NTFS but not write support. If you need to add or change files on an NTFS drive, you have two options: reformat the drive to a Mac-compatible format, or install third-party software that adds write support.
Reformatting erases everything on the drive, so back up any files first. To reformat, right-click the drive in Finder, select Erase, choose a format (APFS for newer Macs, Mac OS Extended for older ones), give it a name, and confirm. The drive will be empty and ready to use with your Mac afterward. This is the cleanest option if you don't need to share the drive with Windows computers.
If you need the drive to work on both Mac and Windows, use exFAT format instead — both systems can read and write to it. To format as exFAT, follow the same steps as above but select exFAT from the format menu. exFAT is slower than APFS or NTFS but works on both systems. Third-party apps like Paragon NTFS or Tuxera NTFS add write support to NTFS drives without reformatting, but they cost money and require installation.
Mounting a drive that doesn't appear automatically
Some external drives, especially older ones or those formatted for specific purposes, don't mount automatically when you plug them in. If a drive is connected but not showing in Finder, try opening Disk Utility (in Applications > Utilities) and looking for the drive's name in the list on the left. If you see it there, click it and press the Mount button at the top of the window.
If the drive appears in Disk Utility but has a red or yellow warning icon, it may have errors or be formatted in a way your Mac doesn't fully support. Click the drive name and look at the information panel on the right — it will show the format type. If it says something like "Linux" or an unfamiliar format, your Mac may need additional software to read it. Search for that format name plus "Mac" to find compatible drivers.
If the drive doesn't appear in Disk Utility at all, it may not be recognized by your Mac's hardware. Try a different USB port, or plug it into a different Mac if you have one available. If it works on another Mac but not yours, the drive may need repair or your Mac's USB controller may need service.
Ejecting a drive safely
Before unplugging an external drive, always eject it first — this tells your Mac to finish writing any pending data and close the connection properly. If you unplug a drive while it's still writing, you can lose files or corrupt the drive's file system. Ejecting takes a few seconds and prevents these problems.
To eject a drive, right-click its name in the Finder sidebar and select Eject. You can also click the eject icon next to the drive name if one appears. Wait for the drive name to disappear from the sidebar, then it's safe to unplug. If the eject option is grayed out, a file on the drive may be open or in use — close any programs using files from that drive and try again.
If a drive won't eject and you're sure nothing is using it, restart your Mac and try again. On rare occasions, a drive may get stuck and require a force eject — hold Command+Option and click the eject icon, or use Disk Utility to unmount it. Force ejecting is safe for the drive but may cause data loss if files were being written at the moment, so use it only as a last resort.
Checking a drive's format and storage space
To see how much space a drive has and what format it uses, right-click the drive in Finder and select Get Info. A window will open showing the total capacity, how much space is used, and how much is free. It will also show the format type — APFS, Mac OS Extended, exFAT, NTFS, or something else. This tells you whether the drive is compatible with your Mac and whether you can write to it.
If you need more detailed information, open Disk Utility, click the drive name on the left, and look at the information panel on the right. This shows the exact format, the partition scheme, and whether the drive has any errors. If the drive shows a warning or error status, you can click First Aid to run a repair scan — this checks for problems and fixes minor ones automatically.
For a quick visual overview of how space is used, open About This Mac (Apple menu > About This Mac), click the Storage tab, and look for the drive in the list. This shows a colored bar representing what's taking up space — documents, applications, photos, and so on. This view is less detailed than Get Info but gives you a fast sense of whether the drive is nearly full.
Accessing a drive that appears locked or unavailable
If a drive appears in Finder but shows a lock icon, or if you see a message that you don't have permission to access it, the drive may be encrypted or have restricted permissions. For encrypted drives, you'll need the password — enter it when prompted and the drive will unlock. If you don't know the password, the drive's owner or the person who encrypted it is the only one who can help.
If the drive shows a permissions error instead, it may be formatted with permissions that don't match your Mac user account. This is common with drives that were set up on another Mac or shared between multiple users. To fix this, you can change the permissions by right-clicking the drive, selecting Get Info, clicking the lock icon at the bottom right, entering your Mac password, and adjusting the permissions. However, this only works if you have administrator access on your Mac.
If you can't unlock the drive and don't have the password, your only option is to erase it — this removes all data and resets the permissions. Back up any files first if possible. To erase, open Disk Utility, click the drive, click Erase, choose a format and name, and confirm. The drive will be empty and accessible afterward.
Frequently Asked Questions
Why doesn't my external drive show up in Finder?
The drive may not be mounted, may need a restart, or may be formatted in a way your Mac doesn't recognize. Try restarting your Mac first. Then open Disk Utility (Applications > Utilities) and look for the drive in the list on the left — if it's there, click it and press Mount. If it doesn't appear in Disk Utility either, the drive may not be recognized by your Mac's hardware or may need repair.
Can I use the same external drive on both Mac and Windows?
Yes, if you format it as exFAT. Both systems can read and write to exFAT drives. NTFS drives work on both systems too, but Macs can only read them without third-party software. APFS and Mac OS Extended formats only work on Mac. To reformat, right-click the drive in Finder, select Erase, choose exFAT, and confirm — this erases all data on the drive.
What happens if I unplug a drive without ejecting it?
You risk losing files or corrupting the drive's file system if your Mac was still writing data to it. Always eject first by right-clicking the drive in Finder and selecting Eject, then wait for it to disappear from the sidebar before unplugging. This takes only a few seconds and prevents data loss.
How do I know if a drive is failing?
Open Disk Utility, click the drive, and look for a warning or error status in the information panel. If you see one, click First Aid to run a repair scan. If the drive makes clicking or beeping sounds, or if files become corrupted or disappear, these are signs of hardware failure — back up your data immediately and stop using the drive for new files.
Can I partition an external drive to use it on both Mac and Windows?
Yes, but it's simpler to just format the whole drive as exFAT. If you want separate partitions, open Disk Utility, click the drive, click Partition, add a new partition, format one as APFS (for Mac) and one as exFAT (for both systems), and confirm. Each partition will appear as a separate drive in Finder. This is useful if you want to keep Mac and Windows files separate, but exFAT is easier if you just need both systems to access the same files.