Sometimes the fix is easy and sometimes it is a bit more complicated.
In this article, I’ll try to go through the different solutions on Mac
and Windows for fixing this issue. How the drive is formatted and what
file system is being used is the most common reason why drive is not
recognized.
Assign Drive Letter
The other main reason is that the drive simply is not being
recognized by Windows or Mac and therefore won’t even show up on your
system at all. This is usually a problem with drivers or hardware. In
order to figure out whether your problem is related to formatting or to
not being recognized, go to
Disk Management in Windows or
Disk Utility on OS X and see if the drive shows up there.
If the drive shows up here, but not in Windows Explorer, you might
have to assign a drive letter to the disk. Normally, Windows does this
automatically, but sometimes because of other connected devices, your
external hard drive will be recognized, but not have any drive letter
assigned to it. In Disk Management, just right-click on the disk and
choose
Change Drive Letter and Paths.
Pick a letter for your drive and you should be good to go. If the
drive is showing, but you’re getting messages about the drive needing to
be formatted, etc., then read the next section below.
On Macs, the drive should automatically appear on the desktop. If
not, go to Disk Utility and check to see if it appears under the heading
External.
If the drive is showing here, but not on the OS X desktop, then click
First Aid
to try and repair the drive. If the drive has a file system not
recognized by OS X, you’ll need to erase it and the format it using FAT
or HFS+.
If the drive is not showing up in Disk Management or Disk Utility at
all, you have some other type of problem. Scroll down to the
Not Showing Up section below.
Format Drive
When it comes to file formats, there are a couple of major formats that are used about 99% of the time:
FAT32 and
NTFS for Windows and
HFS+ (Mac OS Extended) for Macs. Now OS X can read and write to FAT32 formatted drives, but can only read NTFS volumes.
Windows is worse in the sense that it cannot even read or write to
HFS+ formatted volumes by default. You can get Windows to do it, but you
have to purchase third-party software. The only other option is to
format the hard drive and use the FAT32 format for the best
compatibility.
When you connect a HFS+ formatted drive to Windows, you’ll get a
message stating that the drive needs to be formatted in order to be
used.
If you see this message, it just means that Windows does not
recognize the file system on the drive. Make sure you connect the drive
to the appropriate operating system and backup any data that you might
need before performing a format.
So what’s the best format to use so that you can see your hard drive
on multiple operating systems? The legacy format that is most compatible
is FAT32, but it limits you to only 4 GB for max file size. You can
read my previous post on how to
format an external hard drive using FAT32.
If you need support for bigger files, then you should use the
exFAT
format. It’s newer and supports much larger files, but only works with
newer versions of OS X and Windows. You’ll have to be running OS X Snow
Leopard (10.6) or higher or Windows XP or higher.
In Windows, you can choose exFAT as the file system format in
addition to NTFS and FAT32. When you format a drive in OS X using Disk Utility, you can also choose the exFAT format if you like.
Drive Not Showing Up
If you connect the drive to the computer and nothing happens, one of
several things could be going on: your hard drive might have a problem,
the correct software or drivers are not installed on your system, or
there is something not working properly with the operating system. Let’s
start with some common problems and their solutions.
Windows – Device Manager
Sometimes old drivers can cause a device to malfunction when
connected to Windows. You can try fixing this by first going to the
command prompt (Start and type in CMD) and running the following
command:
set devmgr_show_nonpresent_devices=1
Once you do that, open
Device Manager (Start and type in device manager) and then click on
View –
Show Hidden Devices.
Expand out
Portable Devices, right-click on any items that are grayed out and choose
Uninstall. Restart your computer and try to connect the hard drive again.
In addition to Portable Devices, you can expand out
Disk Drives and try to uninstall the device from there if it is not showing up properly in Windows Explorer.
Windows – USB Device
If you connect your USB drive to Windows and get a
USB Device Not Recognized
error, make sure to check out the link on how to fix that particular
problem. Windows tries to blame the device for malfunctioning, but it’s
normally a problem with Windows.
USB Ports/Secondary PC
You can also try plugging the drive into another USB port on the
computer to make sure it’s not a problem with that particular port. If
you are connecting to a USB hub, disconnect that and try to connect the
drive directly to the computer.
The only way you can really tell if the problem is with the computer
or the hard drive at this point is to connect the drive to another
computer. If the drive doesn’t work on another computer, it’s highly
likely something is wrong with the drive itself.
Drive Tools
If it appears that there is a problem with the drive itself, you can
try to download the diagnostic tools from the drive manufacturer. Just
about all the major brands like Seagate, Western Digital, Toshiba, etc.,
have these diagnostic tools.
http://www.seagate.com/support/downloads/seatools/
Western Digital DataLifeguard Diagnostic
Fujitsu (Toshiba) Diagnostic Utility
You can also read my previous post on
checking your hard drive for errors
for more information and more tools to test hard drives. If the drive
has become corrupt or has bad sectors, these tools can fix it.
USB 3.0 Drives
If you have a USB 3.0 external hard drive, there are a couple of
extra considerations you have to take into account. Firstly, make sure
you are using an appropriate cable. I’ve run into several clients that
had this problem and fixed it by simply using a different USB cable. So
try out several cables before you give up.
Secondly, you might need to update the driver in Windows. Again, go to Device Manager, expand
Universal Serial Bus controllers, right click on the one that has
USB 3.0 in the text and choose
Update Driver.
Power Issues
The only other possibilities with this type of problem are lack of
power or complete hard drive failure. Make sure the hard drive has the
correct external power adapter and that the light on the front of the
drive is turning on and is not orange or red. Also, try using different
cables as some are able to carry more power than others.
Hopefully, this article will help you get your external hard drive
recognized by Windows or Mac. If not, post a comment and I’ll try to
help. Enjoy!