Recently my segate 1tb external hard drive has been playing up on my late 2013 MacBook Pro with retina. It has been very inconsistent. sometimes it works fine for a day or two or only 2 minutes, and then other times it doesn't even show up. I have looked in disk utility and I cannot find it there. I tried to run 'first aid' on it in disk utility yesterday but got a message saying something along the lines of "cannot perform first aid because the drive cannot be un-mounted. Thanks in advance for your help!
MacBook – External hard drive not recognised by MacBook Pro.
external-diskhard drivemacbook pro
Related Solutions
This seems like an issue with the chosen file system.
What file system did you choose when formatting the hard drive? If it's not HFS(+), FAT in any fashion or NTFS you cannot read it on OS X without additional software. If it's Ext, you could go with Paragon's Ext for Mac (but it costs some bucks).
In future, best choose exFAT when formatting an external hard drive if you need to use it on different operating systems. It both allows rather large files (which is heavily limited in FAT32), but can be both read and written in all important operating systems.
- Please quit Disk Utility if it is open and launch Terminal in the folder Applications/Utilities/ with your external drive connected
Enter the following command at the Terminal prompt:
defaults write com.apple.DiskUtility DUDebugMenuEnabled 1Press Enter
- Quit Terminal
- Start Disk Utility and enable 'Show every Partition' in the Debug menu
- After a few seconds all partitions should be visible
Mount the partition 'NameOfTheMainPartitionExternalHD' if it is present and greyed out with the blue button Mount. The partition should now be visible on your desktop.
In the above example the external drive is an SD card and the usually visible partition of the external drive is gDisk. Don't touch disk1s1 (Lion) or EFI (Mavericks)
Please check the format of the partition
If the format is 'Mac OS Extended' you might check the drive for inconsistencies.
Best Answer
First off if you notice issues with an external drive like you describe that is the drive trying to tell you that it is failing. Hope you have a backup.
If it is not showing up in Disk Utility you could try rebooting the Mac, with the drive attached, a time or two. Power cycling the drive, unplugging it and plugging it back in, all of which might get it working or might do nothing at all.
If you can get it to mount and there is nothing you need on the drive try re-formatting it. If that fails then you definately have a bad drive instead of just a corrupted one.
If you have a third party disk repair utility (I like DiskWarrior) and it will see the drive run that.
Honestly it sounds like the drive is dying and needs to be replaced, either under warranty or by buying a new one.