Macbook Pro won't mount external hard drive

I have been having this problem with a Macbook Pro late 2006 and a Macbook Pro early 2011.

Macbook Pro refuses to mount an specific external hard drive or USB stick, after being able to do so with no problem before, and usually after the operating system disconnects it suddenly.

That particular external hard drive or USB stick is perfectly good since it works OK under linux.

MBP would mount the drive month later when tried again.

It have happen with two external Western Digital Hardrives (myPassport) as well as with a Kingston USB stick.

Disk Utility sees the drive but cannot mount it because it's "incompatible".

Many people seem to be having this problem and no solution has been found.

I cannot format the disk because that's where my backups are.

Again: a Linux box uses the drive with no problem. I don't have another mac at hand to try.

Now I'm going to buy another external hard drive from Amazon.

Which brand and model should I buy in order not ti have this problem again?

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.

Agreed that it's a file system issue, but if the Mac was able to read and write to it in the past, the file system isn't incompatible with the Mac.
The file system may be damaged to the point where the Mac cannot decipher it anymore, but the Linux machine is more able to work around the damage. The sudden disconnection is also a symptom that the file system is damaged.
Which file system do you use on these disks?

This could be an issue with corruption of the file system/directory structure on the disk.

A utility like Disk Warrior may be able to help you resurrect the directory structure and recover the files.
However, given that this is your "backup" drive I would be concerned that the disk has become unreliable and would seek a new backup repository (as you mentioned buying a new disk, this is a good idea.)

Can you recover the files under Linux? If so this may be a cheaper alternative to consider. Finding a way to back them up somewhere else in order to be able to test the disk or relocate the files to a new backup disk should be the first priority.

If you primarily are just trying to use the files under Mac, then HFS+ (Journaled) is the best choice since it is more robust than something like exFAT. ext2 under linux would be an alternative as there are some solutions to read/write this filesystem under Mac as well.

So:

1. Try a utility like DiskWarrior to recover/rebuild the disk filesystem. Alternatively recover the files under Linux if you can read them from there.
2. Get a new disk to use as a new/second backup disk
3. After copying/recover the original files you may want to reformat and test the original disk with something like a surface scan (TechTool can do this but is expensive, Scannersz Lite is a possible alternative.)

Unfortunately a Verify/Repair under Disk Utility is not that thorough so it will not fully test the drive like you need.

Here's an article on three popular disk tools in OS X http://www.peachpit.com/articles/article.aspx?p=1620209

• Any disk will have a chance to fail over time and external disks are (usually) given harsher conditions. That is not to suggest they can't be used for backup but if the data is really critical it's not unwise to keep redundant copies of those backups.

• No one particular Brand/Model will guarantee this doesn't happen again. You can check the different warranties available which suggests the manufacturer's belief in the reliability of a drive.

• Some disks have 5 year warranties, 3 year or only 1 year. Determine what reliability/price ratio you want to pay for the data you are backing up. Also a refurbished drive will usually only have a 6 month warranty and wouldn't be recommended.

good luck!

I had the same problem. The HDD is NTFS, a 2TB WD MyPassport. I was using it between a PC and a mac for a few months (just got a mac), and this last time I plugged it in to the iMac, it wouldn't mount, including from right clicking on it... I ejected it and unplugged it then I plugged it in a PC. The PC was able to read it just fine. I stopped the drive (safely remove hardware) in windows and then disconnected it. I took it right over to the iMac and now mavericks sees it without a problem.