How To Fix Slow iMac 2012-2020 External SSD [Updated Guide]

This fix works great on any iMac 2012-2020. This is an update on my previous video here: • Fix Any Slow iMac 2012... - it incorporates some changes with APFS cloning (which is not as simple as macOS Journaled cloning) so the main change is that I recommend using recovery mode to install the OS, and then either restore from internal drive or Time Machine backup or start a new installation.
► Parts:
Sabrent 2.5 Inch Sata to USB 3.0 UASP Enclosure: geni.us/sabrentusb
Kingston A400 240GB SSD: geni.us/ssd240gbkingston
► My equipment:
DJI Pocket 2 - geni.us/djipocket2combo
SanDisk Extreme 256 GB - geni.us/sandiskextreme256gb
MacBook Air M1 - geni.us/applem1macbookair
Anker SD Card Reader USB 3.0 - geni.us/ankersd
► Other channels:
/ andytizer
/ pcgamingwiki
► Get the NEW M1 Macs here (Amazon links):
geni.us/applem1macbookair
geni.us/applem1macbookpro
geni.us/applem1macmini
geni.us/applem1imac
Affiliates Disclosure: Andrew Tsai is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites. Andrew also places links for other affiliate links which may earn commissions when viewers follow those links.

[@shazmirshahi4973]

I think you're a genius watching other tutorials they all forget to get you to erase the internal drive after adapting to the external SSD this is a clever and all rounded approach we thank you for this beautiful video you are a godsend to this Earth thank you once again

[@SK-ks3jm]

THANK YOU SO MUCH! Everything loads a lot faster now. I have a late 2015 imac given to me that was updated with Big Sur. The computer was so painfully slow I couldn’t get anything done. I’m not tech savvy at all so your tutorial was super clear and easy to follow.

[@kiprips]

Got a second hand iMac 2019 didn’t realise the HDD would be so slow! Followed the video was able to get a 1tb SSD for £30 case for £10 sorted! Works like a dream.

[@DonDe3zy]

Where did you get that from?

[@nikkeprik]

This is the best thing that ever happened to me in my carreer as a photographer so far! My iMac late 2015 was SOOOO slow, it was absolutely horrible to work with and I was planning to get rid of it. Until someone send me your video. Thank you so so much for sharing this easy and clear technique on here.

[@TorrancePollard]

Hey Nikky, did you do this?

[@ShoaibKhan-qb8by]

Thanks man, I did this with a 500gb ssd and it runs wayyyy faster. I can even access the internal 1tb hdd while booted on the ssd!

[@SergeHoude4U]

Thanks so much for the Step-By-Step Instructions. My iMac 2017 has been rejuvenated 😎

[@MakAttackMusic]

THANK YOU LOOORRRRDDDD for this! This is such a wonderful hack. The blazing speed of my computer after this is quite astounding! My audio/video production software responds so much faster than before. This has saved me thousands in purchasing a new machine. Now I just gotta find some videos to update the OS. Put in a 2T Crucial drive so now I have more room and my computer can breath! This is the closest thing to getting a free computer!😁

[@JohnTheRegis]

Very useful, thank you, I need to extend a late 2013 iMac’s life for a few months and will be doing this soon! 😺

[@warrenpatterson3452]

I tried your original method using CCC which failed as when I booted in recovery mode it only showed the HDD available to boot from. Followed this updated guide and it worked fine! Gone from 40mb/s to 400mb/s read and write speeds, thanks Andy!!!!

[@fayep2666]

Thank you sooo much! It feels like a brand new computer 🙏

[@classiccars1]

Thank you so much for this helpful tutorial.

[@sophieeffyvazquez]

Thank you! This helped me speed up my 2015 Mac.

[@mooganoid]

Superb instruction! You've just saved me as my Fusion HD went askew the other week. I'm currently waiting for the HD case to arrive in the post - thank you for the recommendation, especially regarding the chipset! BETTER SSD RECOMMENDATION: Crucial MX500 Kingston aren't the best these days and the model you recommend doesn't hold out well in tests. Oddly, the allegedly 'superior' Crucial BX doesn't have as good write life as the MX!. - If you have a Fusion drive I strongly suggest getting off it as soon as you can, there's a reason they 'disappeared' from the Apple line.

[@Francis-Stories]

Thanks 😎 bro, all the way from Vienna

[@beneaththefloorboards]

🔥 I watched your older video on this, forgot about this link... Puttered around numbers to get a new computer, really shouldn't now. I decided to try this on my old mac and see if I could extend the life. Ran into problems (CCC really should just tell you this!). Figured this out myself. Wish I'd watched this video first as your process was far easier (mine was the same, just with way more steps), hahaha. Alas. Just finished so haven't really had the chance to experiment with it yet, but seems WAY faster. But wanted to hop on here to say thanks for the idea! (Figured if not this one, then I can easily port to a mac mini!)

[@obscuremusik8900]

I had to do this a couple of years ago when my internal hdd started to fail on my 2015 imac, I ran my os from a 500gb samsung t7 ssd but have recently upgraded to m. 2 NVMe ssd and it's like a new machine 👌

[@sothai.2158]

Huge thank you, I followed your steps and it worked perfectly fine with a Samsung T7 (SSD 1Tb). I resurrected my 2013 iMac !

[@mauriciocastro1549]

I was going to purchase a T7 but opted for the Sandisk Extreme instead. How do you like it, do you have any heating issues since its running constantly?

[@PTonyJr]

After you upgraded the SSD can you then update to a newer OS? What OS are you running?

[@timkaz227]

Would there be much difference if you used an external M.2 via Thunderbolt? I'd like to see that comparison.

[@jokerr1391]

Awesome video , just wondering if I do this on a 2015 iMac , will I be able to have the latest 2022 OS ? Thanks 😊

[@littlemisa6074]

Such a good video. Thank you.

[@vero.saulnr]

Thank you so much. Greetings from Germany.

[@wdungen]

Can you (or others who have done this) share the difference in "seconds or minutes" of the actually improvement time it takes to boot up their computer. What is the before/after time it takes to boot?

[@kolygonz3417]

Please.. is there other way to check or enable UASP support in Big Sur? I couldn’t locate IOUSBAttachedSCSI / IOUSBMassStorageUASDriver extension in the System Report to make sure… or has it been renamed? Anyway, your guide is super helpful, my 2015 iMac has a new life now after following your method (from 40MB/s to 400MB/s) - thank you!

[@markielinhart]

Very useful video, I’m about to do the same thing! Thank you Andrew👏🇦🇺✌️

[@nileshhirani-hz4zg]

Thank you so much for this video. Wanted to ask would it make a difference if I used a PCIe and connected it via USB-C (thunderbolt) or the extra money for this setup has minimal difference? Thanks.

[@mikegord]

Tried useing T5 and T7 Samsung SSD's as boot drives in my 2013 iMac but found a standard SSD worked just as well. I think the T series tech, which is more recent than my 2013 system, negates the SSD speed. So a standard generic SSD in an enclosure works best.

[@rmjaln]

What is the difference between using this type of drive and an NVMe? Would the older Macs not recognise an NVMe?

[@mikewade99]

This is amazing I am using A Samsung T5 1TB SSD and I am getting much more speed.

[@user-lh9cl6be7k]

Jan 2024, Just completed putting my iMac 2019 hard drive on a SSD. Fantastic so happy with the results and a big, big, biggest thanks to Andrew Tsai. What a life saver you are, great video and I did it. Thanks👍👍👍👏👏👌👌👌

[@alexyung5371]

Hello @andrewtsaitips , just wondering why you prefer a USB3 over a thunderbolt 1 connection for this? Thanks!

[@studio93creative93]

Whats the best 2 TB SSD for a bootable drive for iMac27 late 2012. Looking or speed and reliability but with limitation to USB 3.0 port on the old iMac27 late 2012.

[@storyslamoxford8239]

Great video. I bought the same hardware, and was SO looking forward to the possibility of increased speeds on my crushingly slow old iMac, but it won't, won't, won't go into recovery mode. I've tried every fix for that I could find: reset SMC, different keyboard shortcuts, and the rest. I've restarted at least ten times now. Any suggestions?

[@margaretvu3244]

Hi Andrew, do you think I can do all this off a nvme ssd external drive (Samsung 980 pro) with acasis (40gb) enclosure?

[@mytt88]

will this work for working between the older intel macs and the newer m chip macs? thanks

[@kev2427]

Would this work with something like open care patcher? I’m not confident enough to install an SSD in my 2010 iMac

[@sajaalsalami1974]

Hi Andrew, I hope you are doing good, Can I use "Kingston A400 SATA3 Solid State Drive, 960 GB" instead of the 240 GB and would the same enclosure fits this bigger drive ? thanks

[@patricklavoie8719]

So much faster now!!! :O

[@katherinelee9600]

Sorry for the dumb question but when you shut down the computer do you need to switch “off” the button on the ssd as well? Can I also let the computer sleep instead of shutting down completely?

[@janardan23]

Can anyone tell me if the iMac (21.5-inch, Late 2015) A1418 that came equipped with a 256GB PCIe 2.0 x4 also has the needed cabling to add a regular 2.5" SATA-3 SSD? Thanks in advance for reply

[@RickyDeGove]

I'm new to this, but I would recommend not forgetting to enable TRIM support.

[@roysab1]

Hi Andy. The SSD you used in the enclosure: is this an internal SSD or external SSD? I followed your links and looks like this is an internal SSD - wondering if it has to be external SSD...? Thanks for the video!

[@borisvanhoorn2930]

Does this work with an usb stick?

[@cookaloris]

I have a late 2012 iMac and I tried to do this with Catalina. I used a samsung t7 500gb. When I go to "install Mac OS catalina" it only gives me the 1 option for internal HD. It does not show the T7. Any idea why? I did erase and format the t7 in disk utility.

[@thomraller5323]

WOW! What a difference in performance after changing to a new SSD Boot drive. QUESTION: Is it now possible (recommended) to erase the internal HD (1 TB) and use it for Time Machine backups? Cheers, TRR

[@mooganoid]

Plausible BUT, why use a faultering HD as your failsafe? Consider that! ;-)

[@drxksoul]

a question, can i get a pre-made ssd from companies like San-Disk or Samsung , or should i buy a ssd and case for it?

[@KellanAli]

I have a problem. Went through these steps. I have an imac late 2012 and a t7 500gb external ssd. When I went to restore mode and disk utility and then erase, all was going well. Then when it rebooted, it rebooted into lion, which is not what my imac was running. I was running Catalina. I saw in the video you said it will boot to whatever firmware os your imac has, so mine must be lion. But now what? Now I seem to be stuck in lion. Trying to figure out how to upgrade to Catalina.

[@ascii2795]

Why do you use an internal SSD and an enclosure as opposed to an external SSD? Just trying to understand which is the better way to go. I have a 2015 iMac if that is relevant. Thanks so much for the video

[@AtomCoder]

It's an easier option rather than have to remove the screen and replace the internal HDD with an SSD. However, over the long term it would be better to replace the internal HDD.

[@jeffsalvador8586]

Is there a method for an iMac 2011?

[@alanjupp363]

I have a late 2012 21.5" OS Catalina V10.15.7 8GB 1600 MHz DDR3, Processor 2.7 GHz Quad-core Intel Core i5 and a 27" mid 2011 OS High Sierra V10.13.6 32GB 1333 MHz DDR3, Processor 2.7 GHz Intel i5 - Will this fix (I have watched both videos) allow me to keep the OS updated as it will sit resident on the new SSD?

[@archstanton9703]

For a 1GB Kingston 960GB and the Sabrent enclosure is almost the same price of a 1GB Samsung T7 external SSD. Would the Samsung T7 drive work? I have a super slow iMac that was slow right out of the box and I’d like to get a couple more years of use before I buy a MacBook Air or Pro. Thanks for making these two videos!

[@vijisrangoli]

Yes, you can

[@archstanton9703]

@@vijisrangoli Thanks

[@madhuhadas15370]

how fast does it boot up with this ssd?

[@daleanderson3575]

Hi, do you have to erase the internal drive for optimum performance, or can you leave everything on just as another backup?

[@Theiris92]

I left a similar comment just a min ago, did you ever find out? Mine is not letting me delete the internal drive, but I am still able to log into the external drive fine. Just wondering if it will affect anything?

[@heathmorgan]

Hi, I have just used this video to connect up to an external ssd, thanks for that, just wanted to know if I wanted to fit the ssd internally, is it just plug and play or is there more to it than that? ( I know about the actual screen off etc) Thanks again

[@andrewtsaitips]

Yes just use the cloned SSD and put inside the iMac see kzbin.info/www/bejne/eJDGkp9pj555pK8

[@heathmorgan]

@@andrewtsaitips So it will recognize it as an internal drive and I will have to do nothing with the saved files etc, sorry to be dim

[@techmap4191]

Andrew if I decide to put this SSD inside the Mac after doing this , are there any changes I need to make or will this just need to be installed internally and that’s it? Also, is it any faster for me to put it inside the computer as opposed to just leaving it out as an external bootup??

[@andrewtsaitips]

No changes, no real difference in speed.

[@IndianaGraphics]

Very helpful, BUT!!! Why would you sacrifice storage? You went from 1TB to 500 GB. Thank you

[@andrewtsaitips]

Same reason why I didn’t upgrade it to 4TB SSD, I didn’t need the space!

[@_1mm]

Thanks for the video!!! It helps and I would like to ask for your valuable and professional feedback before I invest in my iMac I have a 2017 iMac version bought in early 2019. Normally it is good though I’m using iMovie for video editing. Smooth However I recently start live streaming mobile games and it becomes slower and lag on screen. What would you recommend me to upgrade it with external improvement (I’m an IT idiot and hell no idea to improve inside) Thank you very much and indeed for your previous time and consideration to reply me :):):) My IMac version is Retina 5K, 27-inch, 2017

[@drxksoul]

what are the chances for me to have the same mac and the share the same problem :(

[@joeprete7424]

Can I install Mac OS on an external SSD from another Mac, then use it on the (late 2009) iMac? My HDD has many problems!

[@iwayanpartama9241]

Yes, you can

[@budilistoro4057]

Hey man i already got to recovery mode but why my wireless mouse isn’t conect to the mac 😭 anyone could help me?

[@simonlord7248]

I've recently followed your excellent video and my Mac is certainly much faster. I haven't been brave enough to delete the old Macintosh HD yet and I have found that I am unable to download anything from Safari, I get a message saying there isn't enough disk space. I have checked and the download destination appears to be "Downloads" on the new SSD. Any ideas?

[@andrewtsaitips]

Use this tool kzbin.info/www/bejne/bIebgJ2dpNiqrbM

[@MyOhwhatever]

Does anyone know the actual performance difference using this external SSD with the Fusion drive in iMac 2015? I am using iMac 2015 and am thinking if it’s worth to do what is suggested here!

[@daktarioskarvannederhosen2568]

the fusion model boots quite quickly but the lion's share of the fusion drive is a hdd.

[@mooganoid]

I'd get off the Fusion drive as soon as you can, they're known to fail. Mine did out the blue, and with only light use!

[@davefisher538]

Hi there...I have a mid 2011 iMac, and I would like to use the 512GB SSD I have purchased, The iMac is presently using High Sierra 10.13.6 and to be fair my full kettle boils from cold before the iMac boots up (which is handy if you like a nice hot cup of tea) so I attempted the method you advised for a 2012 iMac, and it was simply sat displaying "Starting Internet Recovery. This may take a while." With a rotating picture of the Earth spinning. I wonder if you could advise what I should do when that happens as after ten minutes the same screen is still displayed? I have a Lightstream Fibre Optic internet connection, and the computer was tested prior to connecting the SSD into the USB slot at the rear of the iMac and showed it was connected to the router. Any ideas please?

[@andrewtsaitips]

If internet recovery doesn't work then you can 1) download High Sierra installer and then install it onto the USB or 2) make a bootable USB flash drive using a High Sierra installer and boot from that instead.

[@vboutique2188]

Could you use a nvme drive in a external box as well?

[@andrewtsaitips]

Yes but you’ll never get full speeds from USB 3.0, might as well save money using SATA.

[@abuadam2970]

Can this work without the internal sata to USB 3.0 enclosure?

[@daktarioskarvannederhosen2568]

yes

[@gimmosleep7922]

Hi! Cmd R does not work after I hold alt. It just tells me that it starts recover from internet. Is there something I can do?

[@andrewtsaitips]

That’s right just let it recover from internet and then you’ll get to the next stage.

[@gimmosleep7922]

@@andrewtsaitips Thank you very much for your response! I will try this

[@gimmosleep7922]

@@andrewtsaitips So, I tried several times but the iMac never goes past the "turning globe" symbol. Can I put a bootable OS directly onto the ssd?

[@gimmosleep7922]

For people with the same problem, creating a bootable ssd worked in my case. I think my internal HDD was broken and I just could not access any of the shown menues. I followed the steps shown in the video with an older iMac that still worked and later plugged the bootable SSD in the iMac with the broken HDD. After that I could hit "alt" on my windows keyboard and select the SSD! Works perfetly fine

[@covfefeindia9466]

Hi. It seems very simple and I did it as suggested by you. The only problem I had was the external SSD gave an error upgrading to the latest version of the iOS twice at the last 3 minute during the update. I went ahead rebooting and tried booting the iMac through the external drive. But it is just shutting off as soon as the Apple logo comes up. I’m able to boot through the internal HDD but it restarts after I login to the system. This keeps happening. Help me rectify as I’m unable to boot now with both the internal and external drive.

[@vijisrangoli]

Solved your issue?

[@marcuslee3051]

I face issues with my SSD moving around on the table which causes the Mac to stop working. Anyone face this and do you have a workaround? I basically weigh the SSD down on the table but sometimes micro movements can cause the computer to hang too...

[@andrewtsaitips]

Get some tape and tape I’m the SSD and cable to the back of your iMac.

[@moneygettingmovement7901]

Mines restarded when downloading and just showed a folder with a question mark

[@danbulmer]

trying this out out on a 2017 iMac with Monterey. Fingers crossed. This iMac has a 5400RPM Hard drive.... :)

[@derekgibbs8966]

I’m just about to do all of this wish me luck

[@andrewtsaitips]

Good luck!

[@Theiris92]

Does anyone know why I may not be able to erase the internal HD? I’ve managed everything up to the point where you should erase internal hd. I’m new to doing this lol, any tips would be appreciated! Is it essential that i erase it? I seem to be able to log in to use the external ssd fine now that I’ve installed it and followed all the other steps…?

[@kylepalmer4833]

Same here, I am haing the same issue. The erase option for the fusion drive is greyed out and not clickable.

[@ACohen]

Internet Recovery (cmd+opt+R) would have been better, since that installs latest OS.

[@tomadams2734]

Followed this step-by-step, but when it gets to the end of the initial OS download it just re-boots my iMac and brings me to my normal log in screen. I'm downloading Catalina not Big Sur, but should that matter? Any help much appreciated!

[@andrewtsaitips]

What SSD are you using? I’ve found some don’t work well if you aren’t using an enclosure.

[@tomadams2734]

@@andrewtsaitips I’m using the Kingston SSD you recommend in a UASP enclosure. I’m trying to improve my late 2013 iMac. Any help you could offer would be much appreciated!

[@daktarioskarvannederhosen2568]

i don't think you even need the external ssd enclosure case.

[@edge4006]

You could of cloned your internal drive when you were in disk utility and skipped all those steps.

[@iainet]

My desire to continue watching your video diminished after having to watch that unskipable Deep Heat advert for the third time in under 5 minutes.

[@EDDIEGARAGE]

Why needs to flick you hand all over the screen, no good

[@KANA-rd8bz]

Tutorial is horrible

[@iainet]

My desire to continue watching your video diminished after having to watch that unskipable Deep Heat advert for the third time in under 5 minutes.