iMac Intel 21.5" EMC 2308 Hard Drive Replacement

Featured Guide

Featured Guide

This guide has been found to be exceptionally cool by the iFixit staff.

Replace the hard drive in your iMac Intel 21.5".

Upgrade your hard drive for an increase in storage space.

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Edit Step 1 Glass Panel  ¶ 

  • Before beginning, unplug your iMac and lay it on a soft surface as shown.

  • Stick a suction cup near each of the two top corners of the glass panel.

  • To attach the suction cups we sell, first position the suction cup with the movable handle parallel to the face of the glass panel. While lightly holding the suction cup against the glass, raise the movable handle until it is parallel with the other handle.

  • If your suction cups refuse to stick, try cleaning both the glass panel and the suction cup with a mild solvent.

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Edit Step 2  ¶ 

  • Gently lift the glass panel perpendicular to the face of the LCD enough to clear the steel mounting pins attached along the underside of the top edge of the glass panel.

  • Pull the glass panel away from the lower edge of the iMac and carefully set it aside.

  • During reinstallation, be sure to meticulously clean the inside of the glass panel and the face of the LCD as any dust or fingerprints trapped inside will be annoyingly visible when the machine is turned on.

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Edit Step 3 Display  ¶ 

  • Remove the eight 8 mm T10 Torx screws securing the display to the outer case.

  • The last two pictures are detail shots of each side of the display.

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Edit Step 4  ¶ 

  • Slightly lift the top edge of the display out of the outer case.

  • Do not lift it too much. There are several cables attaching the display to the logic board.

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Edit Step 5  ¶ 

  • Pull the vertical sync ribbon cable out of its socket on the LED driver board near the top left corner of your iMac.

  • The vertical sync ribbon cable has a ZIF style end, but the socket has no lock or retaining flap. Simply pull the cable away from its socket toward the optical drive side of the iMac to disconnect it from the LED driver board.

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Edit Step 6  ¶ 

  • Rotate the display out of the outer case enough to disconnect the LED backlight power cable from the LED driver board.

  • Disconnect the LED backlight power cable by depressing the locking mechanism while pulling the connector away from its socket (toward the bottom edge of the iMac).

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Edit Step 7  ¶ 

  • Squeeze the two display data cable connector arms together to unlock it from its socket on the logic board.

  • Pull the display data cable connector away from its socket on the logic board.

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Edit Step 8  ¶ 

  • Disconnect the LCD thermal sensor cable connector from its socket on the logic board.

  • If your fan is spinning full speed after completion, check this connection or the hard drive's thermal sensor cable.

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Edit Step 9  ¶ 

  • Carefully pull the display toward the top edge of your iMac and lift it out of the outer case, minding any cables that may get caught.

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Edit Step 10 Hard Drive  ¶ 

  • Before disconnecting the thermal sensor cable, take note of its orientation. It is extremely important to reinstall the connector reversed from the current orientation so the fans will not run at full speed.

  • Disconnect the thermal sensor by pulling its connector away from the side of the hard drive.

  • During reassembly, be sure that the thermal sensor connector is connected to set of pins closest to the SATA connectors. If the fans spin at full speed, reverse the connector's position.

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Edit Step 11  ¶ 

  • Disconnect the SATA data cable by pulling its connector away from the hard drive.

  • Use the flat end of a spudger to help disconnect the SATA power connector from the hard drive.

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Edit Step 12  ¶ 

  • Remove the two 9 mm T10 Torx screws securing the upper hard drive bracket to the outer case.

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Edit Step 13  ¶ 

  • Slightly rotate the hard drive out of the outer case and lift it up off its mounting pins toward the top edge of the iMac.

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Edit Step 14 Hard Drive  ¶ 

  • Remove the two T8 Torx screws securing the upper bracket to the hard drive.

  • Remove the upper bracket from the hard drive.

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Edit Step 15  ¶ 

  • Remove the two T8 Torx pins from the other side of the hard drive.

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Edit Step 16  ¶ 

  • Carefully peel off the piece of EMI foam attached to the front of the hard drive.

  • Don't forget to transfer this to your new hard drive.

To reassemble your device, follow these instructions in reverse order.

For more information, check out the iMac Intel 21.5" EMC 2308 device page.

Required Tools

TR8 Torx Security Screwdriver

$5.95 · 50+ In stock


$2.95 · 50+ In stock

Heavy-Duty Suction Cups (Pair)

$14.95 · 50+ In stock

Related Products

1 TB 7200 RPM 3.5" Hard Drive

$99.95 · 7 In stock

Universal Drive Adapter

$29.95 · 50+ In stock

Comments Comments are onturn off

Make sure the hard drive is of the same producer and it has a temp sensor connector. It's the only way to ensure that the heat sensor connector will fit into the hard drive's socket. If you don't plug in the temp sensor iMac's HDD Fan will rotate at its maximum speed, ie. over 6000 rpms - the noise is extraordinary!!!

David Relich, · Reply

I replaced my internal HDD on my 215" iMac, but the iMac can't get access to the new hard disk's (Seagate Barracuda Green) temperature sensor. The HDD fan in the iMac steps up the RPM, and over about 15min reaches 6000RPM (VERY loud) and stays there until machine is shutdown or put to sleep.

I found a fix for this: - this tiny piece of shareware software allows the iMac to see the temperature of the drive via S.M.A.R.T., and therefore the fans react according to the correct temperature again!

Ian, · Reply

One thing Andrew left out here, which I discovered on my own, is that even if you have the temperature sensor connected to the correct pins, you ALSO have to make sure that it is 'oriented' properly.

On the sensor connector (the little head that plugs into the hard drive) I saw a little white dot on one side, which it turns out, indicates that's the 'top'. So on my iMac, you have to make sure when you connect the temp sensor connector with the white dot showing.

Otherwise, I got the 6000 rpm fans.

robert Seith, · Reply

Success. For any interested people, it's about an hour - going slowly. Now that I've done it, I assume I could do it again in 15 minutes if I had to.

Just have the right tools handy, the T 8 and T 10 bits in particular. Getting off the display screen is easy. The screws are harder than you'd think because of the magnets, but they're not that bad. I recommend having tweezers to help pull them and place them later on.

Overall, the thing that worried me most was the fan issue. And, so far... it's not an issue. I had a seagate 500 gb, and I replaced it with a seagate barracuda 3 tb hhd. Everything fit right into it, just as it did into the original. No optical sensor needed. No new sensor needed, period. No software needed. Nothing. Just put in the new hd, and it works. I'm very pleased, and very proud of myself. Good luck to anyone considering doing this upgrade. You can do it, really.

Kevin, · Reply

It's a pretty straightforward procedure. Took less than an hour. I replaced the 500GB Seagate Barracuda with a Seagate Barracuda 2TB, model ST2000DM001. So far, after about 30 minutes of use, it's working great, and I haven't had the fan problem, but we'll see what happens.

Kevin's advice about the tweezers for extracting and inserting the screws that attach the display to the case was right on (although I used a small pliers instead).

Before you begin the replacement procedure, I highly recommend putting the new drive into a hard drive dock, and restoring to it from a Time Machine backup. Try booting off the new drive once to make sure it works. Then, when you swap the new drive for the existing internal drive, it'll be ready to go with no further effort needed.

eshienbrood, · Reply

The removal of the screen (step 1&2) can easily be done with just a normal plunger. No need to go and buy suction cups.

Jon Ingi, · Reply

Screen removal was easy with the suction cups. I replaced my Western Digital 500GB blue drive by another Western Digital Blue 1TB because I thought I'd avoid the fan issue but finallythe fan started running at 6000rpm. I ended up buying the software at to correct the issue.

Steven Vandal, · Reply

Anybody here knows anything of update to SSD? I can't find any tutorial on the net.


Thomas Olsson, · Reply

What kind of update?

Scott Dingle,

I replaced my 500GB Hitachi drive with a 1TB Samsung 840 EVO SSD yesterday. I have only two significant remarks:

# To fit a 2.5" SSD in the 3.5" HD bay, you must use some kind of brace/adapter. Some SSDs can be bought in kits which include an adapter; mine didn't, so I bought a Deltaco brace.

# There's no connector for the apple temperature sensor on the SSD. You must either disable the apple fan control or buy an external sensor.

** You can disable the fan control by short-circuiting the sensor cable. This fools the apple fan control into believing the drive is forever cool. This is what I did.

** You can install some kind of software which overrides the apple controls. I did this, too, using Macs Fan Control.

** You can attach an external sensor on the SSD and connect the sensor cable to it. I would have liked to do this, but I couldn't find any reliable information on which sensor to buy.


Could someone tell me what are the signs of a damaged vertical sync ribbon cable ?

I have backlight issue: extinctions.

Only occurs when Energy saver is on (!??).

Bernstein, · Reply

I called Seagate July 22 2013 . They claim that " Seagate never made this HD and it was modified by apple " They also insisted the Sensor connector was a " Jumper option block " . Also they have no replacement telling me " Any SATA Seagate would work . I also called many retail HD sellers and all gave me the same incorrect info . I even sent photos of the HD connector and the MB connector and all insisted it was only a Jumper block and all HDs have them . So much for Tech Support . I did find some original Apple HD for $ 225 to $ 400 . I installed a standard HD and will try the Software Speed Control described in this fine iFixit guide .

To pull the front plastic lens I used the Windshield mount from a GPS .

David Anthony, · Reply

It is not necessary to remove any connectors or cables from the LCD to the MB . Just lean the LCD back about 5 inches . Use a 1/4 inch ratchet wrench with a 1/4 socket to hold the Torx bits , or a short Torx screwdriver . Unscrew the 2 HD screws , lean the HD up out enough to disconnect the 3 connectors . I do not like the Orange suction cups also . They are very stiff and also have a metal screw in the center off the cup which might put a mark on the plastic lens . I use GPS car windshield mounts . The lens is very easy to pull off . The locater pins on the lens Bezel are poorly attached and may fall off . Super glue them back on or just forget them as they are really made to make factory assembly faster .

David Anthony, · Reply

Fan Control Software : I used this Free software for controlling the speed of my fan . It seems to work after 5 hours of testing . Link to site ( ) .

David Anthony, · Reply

I also try this software, but I'm not happy with it! The fan is always hearable and runs always with min 1100 rpm. Before the HDD replacement I rarely heard a noise from the fan!

And how can I now uninstall this software?


Upgraded to a 2TB, 8GB SSD combi from Seagate - as recommended same company as the HDD which was in the iMac - scary to do but with a little help (holding the screen whilst I unplugged the cables, and reverse) it worked very well indeed - bought the tools through Ama(XXX)on in the UK and the company charged a fortune - did not find the iFixit EU shop which has the same prices as the US one

GREAT job with these instructions - would have had to rely on a sloppy shop to do it otherwise...

Only getting back to status quo ante is proving difficult due to not quite working time-machine.

Mathis, · Reply

I had the same experience as eschienbrood- replaced a 500 GB Seagate with a 1 TB Seagate; took about an hour, and would've gone faster if I hadn't dropped one of the screws for the monitor into the chassis. Replacing the 8 screws for the monitor was by far the hardest part of the operation. The heat sensor for the HD went in the same way as it was on the old drive, and there are no fan problems.

Ken Russell, · Reply

great guide ! I replaced my four year old 500Gb classic hard drive by a Samsung SSD 840 EVO 500GB. The HD's internal temperature sensor I replaced by a original DVD drive sensor (ordered @ / Apple part# 922-9229, Hard Drive Temp Sensor Cable 2009/2010 iMac 21", 27", $20.81) and mounted the SSD in two 2,5" > 3,5" adaptor brackets. Be careful, use ESD protection when working inside your iMac. First I put a "ESD protection bubble plastic sheet" on the table, then on top aluminum foil for the display and the glass panel. The iMac was on a real ESD carpet on top of the (ESD) plastic and grounded.

Jean, · Reply

Change "Before beginning, unplug your iMac and lay it on a soft surface as shown." to "Lay your iMac on a soft surface as shown"

Henry Barnett, · Reply

my imac power sullye not powering

tahir, · Reply

imac 2544 2.5 core i5 i touched the motherboard to supply and it spark now it is not powering

please tell me the directions

thanks witting for answering .

tahir, · Reply

Im sorry to say, If it sparked when you touched it your motherboard s now fried. You need a new one.

Robert Wacker,

in Step 7, my connector (new 21.5 iMac - Dec 2010) was not attached that way and just came of easily.

erin, · Reply

I don't understand how to reverse the thermal connector. There's only one way to insert it; unless they mean to reverse the grey and black wires? Confused, but hoping I don't have any fan issues.

Ben Dunkle, · Reply

I had the same problem, i have the fan running at high speed, the connectors cannot be reversed. There is only one way to insert on either end.


Apple used more than 1 brand of hard drive, so some temperature sensor connectors are different.

Andy, · Reply

I still don't understand the instruction to reverse the connector. A photo would be helpful. Does this mean to take the connector and turn it upside down from how it was originally connected? What if the socket for the connector will only allow it to be inserted in one manner? I've changed out my hard drive and the fan is on high all the time, so something is wrong, though I thought I had followed the instructions carefully.

youcan, · Reply

Did you previously have a Toshiba hard drive in your iMac?

Scott Dingle,

Didn't reverse. I changed a 500GB Seagate Barracuda to a 2TB Seagate Barracuda with no issues. It would have been helpful if this article had indicated the old and new drive.

Robert, · Reply

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