Virtually of united states utilise some kind of external storage device with our Mac at some time or another, whether it's a USB stick, flash drive, external hard disk drive, or SSD. Virtually of the time, at that place's no problem. Withal, you may encounter errors at present and again, and one of the most common is that your Mac is unable to write to the disk. You lot may see a message telling you that the bulldoze is read-simply. Fortunately, it's not too difficult to fix the trouble. In this article, we'll prove you how.

What causes the "read-only" error?

In that location are two possibilities when you lot see a message telling you a hard bulldoze, USB stick, or other external storage media is read-only.

  1. The drive is formatted in a way that means your Mac can read it but not write to it. This tin happen with disks that are formatted as NTFS.
  2. Some permissions settings preclude your Mac or your user business relationship from writing to the disk.

To determine which of these is causing the problem, select the deejay in the Finder and press Control-I, or right-click it and choose Get Info.

Under General, yous should see a listing of parameters. Await at the 1 named Format. If it says NTFS, that's the problem.

If the Format is APFS, macOS Extended, or FAT 32, then that is not the problem, and you'll need to bank check permissions.

  1. Expect at the bottom of the Become Info window.
  2. Under Sharing & Permissions, it volition tell yous what access you accept. If it says "read-only," y'all know the problem is permissions-related.

Tip:

CleanMyMac X's Maintenance module allows you to repair broken permissions on a disk with a couple of clicks. That might be all you need to do to ready problems with only being able to read from external disks.

Repair disk permissions in Maintenance module CMMX

How to change permissions on an external hard drive on your Mac

The post-obit applies whether the drive in question is a difficult drive, USB stick, SSD, or any other external media. There are several options, depending on what you identified every bit causing the trouble.

How to fix hard drive read-simply issue

At that place are two options hither. One is to reformat the drive to a format your Mac can write to as well as read. This will wipe all the data from it, so you should brand a backup or manually copy important files to another location first. Depending on how you format it, it may likewise cause issues if y'all need to use the bulldoze with a Windows PC. So, only choose this option if y'all know the bulldoze will simply be used with Macs in the future.

The other option is to utilize third-party driver software to enable your Mac to write to an NTFS-formatted disk. There are a number of paid-for and some free options bachelor.

How to reformat an external drive:

  1. With the drive plugged into your Mac, go to Applications > Utilities and launch Disk Utility.
  2. Choose the external disk in the Disk Utility sidebar.
  3. Select the Erase tab.
  4. Type in a name for the reformatted drive.
  5. Select MacOS Extended (Journaled) from the dropdown menu.
  6. Press Erase.
  7. The bulldoze volition exist wiped, reformatted, and when it'south done, your Mac will be able to write to it.

How to set up permissions problems

If the bulldoze is correctly formatted for the Mac and yous tin't write to it, the problem is likely to exist related to permissions. Here's how to fix information technology.

  1. Select the drive in the Finder.
  2. Press Command-I to brandish the Get Info window.
  3. At the lesser of the window, click the arrow next to Sharing & Permissions to display permissions.
  4. Click on the Privilege menu next to your username and choose Read & Write.
  5. Close the Become Info window.

If your user account is not an admin user, yous may have to use the padlock to unlock permissions settings and type in an admin username and password. You may as well demand to restart your Mac to become the change to accept effect.

In some circumstances, you may not be able to change permissions in the Finder, or doing so may not fix the problem. If that happens to you, the adjacent step is to employ Disk Utility to gear up the disk.

  1. Go to Applications > Utilities and launch Disk Utility.
  2. Select the external disk in the sidebar.
  3. Click on First Aid.
  4. Press Run to confirm that you want to try and repair the disk.

In versions of macOS upwards to and including macOS ten.10 Yosemite, you could use Disk Utility to repair permissions. The choice appears in the Beginning Help tab with two buttons, 1 to verify and one to repair permissions. If you are running a version of macOS where these options are bachelor, you should use them instead of the steps described above.

If you encounter an event where a hard drive is read-only on your Mac, or perhaps a USB stick or flash drive, it may be that it is formatted as NTFS, which can exist read by macOS simply non written to. It may also be a permissions issue. If you follow the steps in this article, you'll be able to identify which information technology is and fix it speedily.