Fix The Disk You Insert Was Not Readable by This Computer

"there was no problem for your USB flash drive when you inserted it with my Windows PC. However, after I brought it home and connected with my Mac, I saw the message ’the disk you inserted was not readable by this computer’. What’s wrong? Why the USB disk inserted was not readable by this computer? There are so many precious family photos and videos. Please help me."

Mac performs well while surfing on the internet and does the tasks. However, as for compatibility, it is not as good as Windows OS. After all, macOS is newer and quite different. While connecting the external hard drive with Mac, you may face the external hard drive is not showing, there is no file on the external hard drive, and even "the disk you inserted was not readable by this computer" in macOS.

Whenever you see the message "the disk you inserted was not readable by this computer" on Mac, then there must be a problem either for the Mac or external hard drive. You can follow the guide below to check out what has caused the problem and how to solve it.

1^st, connect your external hard drive, USB flash drive, or SD card with your Mac, checking out whether it can appear on your Mac or not. Generally, there should be no problem with the hard drive to appear. If not, set up your Mac by going to Finder > Preferences > General, keep the option "Hard disks" and "External disks" checked. If the external hard drive appears on Mac, then you should move on to the next possible solution.

2^nd, check out the file system format of the external hard drive. You know that some formats, like NTFS format is not supported by Mac at all. If the external hard drive is in NTFS format, then you must format it and choose FAT32.

Here are the steps for how to format an external hard drive on Mac:

1. Connect the external hard drive with your Mac.
2. Go to Applications > Utilities and launch Disk Utility.
3. Click on the external hard drive in the sidebar > click Erase > type in the name for the formatted disk > choose a format from the list > confirm the action and click Erase.

Please note that formatting the external hard drive will erase all data on it. To prevent data loss from the external hard drive, you’d better get a copy of all the files or try iBeesoft Data Recovery for Mac to retrieve formatted files on macOS.

3^rd, if formatting still not solve the problem of "the disk you inserted was not readable by this computer", you need to repair the unreadable external hard drive with Disk Utility.

1. Connect the external hard disk with Mac.
2. Go to Go > Utilities > launch Disk Utility.
3. Select the volume in the left panel > click First Aid > select the destination where you can install the Adobe application and then click Repair Disk

tips: You can also use this way to fix an uninitialized disk on Mac.

4^th, if you have tried the above mentioned 3 solutions, the problem "the disk you inserted was not readable by this computer" in macOS still pops up, then here is the last resort, initializing the disk.

Important: if you worry about data loss from the external hard drive, try the best Mac data recovery software to save the data on the external hard drive before you getting down to the task.

1. Download the file recovery software on your Mac. Install and launch it. In the start-up window, select the wanted file types to recover and click "Start".
2. In the next step, choose the external hard drive as the target hard drive and click "Scan" to recover files from formatted disk on Mac.
3. In the scanning result, select found files and click "Recover" to save them on your Mac first.

It’s the Mac hard disk recovery process from the unreadable external hard drive on Mac. I suggest you try the "Deep Scan" in the result window. It will save more files from the external hard drive for you, reducing the risk of data loss.

Here are the steps for how to initialize the external hard drive on Mac:

1. Click on the "Initialize" button. Launch the Disk Utility > click View > Show All Devices in the menu bar.
2. Choose the unreadable external hard drive in the left panel and click First Aid.
3. Click Repair Disk and wait for it to finish. If it warns you that it can’t repair disk, you should navigate to Erase to erase the external hard drive.

The above are the possible solutions you can make use of to fix the problem "the disk you inserted was not readable by this computer". If no solution is workable, you’re suggested to take it to the seller to repair or replace it.