How do I change an imac hard drive

If this really is a 2019 or 2020 iMac 27 5k:

— The 2019 came with a Fusion drive of 1TB size, with options of a 2 TB or 3TB Fusion drives. Fusion is a combo of two drives. The larger is a conventional 3.5-inch 7200rpm mech hard drive; the smaller is tiny blade-type SSD. The two drives are linked by software to act as one.

— The 2020 storage was blade SSD only

In the 2019 , the HDD is in a regular drive bay. The SSD is socketed, but on the back side of a logic board, requiring almost a complete gut job to access.

In the 2020, the SSDs are soldered in place and cannot be upgraded without a full logic board swap. $$$$

You are asking about opening a computer Apple designed not to be opened by mere mortals. There are sad stories in these forums about end users trying to open a 2012 -2020 iMac and breaking it.

So.... your better path is to state WHY you want to change the drive. We may be able to point out options, like the external SSD that PRP_53 wisely mentions, that do not require breaking your computer.

PRP_53 wrote:

Predicated on your user by-line >> " iMac 27″, macOS 15.3 "

This might narrow it down to >>

• iMac (Retina 5K, 27-inch, 2020)

• iMac (Retina 5K, 27-inch, 2019)

Now here I would need some help.

The 2020 iMacs only shipped with SSDs. As far as I know, you cannot upgrade internal storage on these iMacs; the flash chips are soldered to the motherboard.

You can get some aftermarket storage upgrades for the 2019 iMac, e.g.

Other World Computing – OWC Solid State Drives For iMac 27-Inch (Late 2013 - 2019)

There are footnotes about it only being possible to install OWC's 2.5" SATA SSDS "in iMac models that came with a factory-installed HDD or Fusion drive." That might suggest that on iMacs which came with SSDs, Apple left out the connectors you would need to install a 2.5" SATA HDD or SSD of any type.

For other Macs, OWC sometimes has notes to the effect that unless the Mac came with a Fusion Drive or a SSD, you can't install an aftermarket circuit board stick SSD. (Same reason: Apple leaving off a connector which they, themselves, did not absolutely need to have for the original configuration.)

Opening the computer will require spacial Tools unique to Apple Devices

Then there are the Seals for the Display that are very touchy

All this, Before you start mucking around inside the machine to disconnect the drive(s) and replace them with exact right Drive and connections

rkaufmann87 wrote:

Use:

https://eshop.macsales.com/installvideos to find the correct video for your machine.

Thank you 😎

Hope OP has a good look at this 🤞

iMacs have been in production for over 25 years in hundreds of configurations, it would be VERY helpful if you at least told us the model year and screen size of the computer. Without knowing that we cannot answer your question. I strongly recommend that you look over Writing an effective Apple Support Communities Question prior to posting a question so you know the bare minimum we need from you in order to answer.

Predicated on your user by-line >> " iMac 27″, macOS 15.3 "

This might narrow it down to >>

• iMac (Retina 5K, 27-inch, 2020)
• iMac (Retina 5K, 27-inch, 2019)

Now here I would need some help.

As to where the Internal Drive or Drives in the case of the Fusion Drive configurations are Soldered to the Logicboard or Not, I do not know

Opening the computer will require spacial Tools unique to Apple Devices

Then there are the Seals for the Display that are very touchy

All this, Before you start mucking around inside the machine to disconnect the drive(s) and replace them with exact right Drive and connections

A less elegant method is the purchase a good Drive Enclosure and a good SSD Drive from a reputable seller like www.owc.com

Install the Operating System Directly onto the External Drive and run the computer from that drive

Use an external SSD as your startup disk … - Apple Community

Use:

https://eshop.macsales.com/installvideos to find the correct video for your machine.

Thx