iMac 2021 M1 possible internal drive replacement

-g wrote:

D.I. Johnson >> When it fails, you will have to replace the computer, or the logic board at the very least.

are you saying m-series iMacs cannot be used from an external ssd when the internal ssd fails?

Yes, I am saying that. The storage is soldered to the logic board and is integrated to the cpu. If the storage fails, it compromises the secure functions of the OS and the cpu. If the Mac cannot communicate with its on-board storage, it will not boot from an external drive, either.

Make sure you have up-to-date backups of all your stuff. Always.

No. There is no separate 'internal drive'.

The CPU, RAM, and storage are a single chip.

Download etrecheck and post the report it generates here. That will give us an idea of what's wrong.

There is no hard drive.

There is a SSD. The SSD controller is part of the M1 chip. The flash chip(s) are not part of the M1 processor, but they are soldered to the motherboard, and because the M1 encrypts and decrypts their contents in real time, the contents of those flash chips must be kept cryptographically "in sync" with the M1 chip.

(The desktop M2 Ultra Mac Pro minitower has its flash modules on removable boards, but those are raw flash modules, not standard SSDs. Because of the encryption, if you install a SSD upgrade kit in that Mac, you will then need the assistance of a second Mac to revive it, if you want the Mac Pro to be more than a large brick.)

If the SSD fails completely, you are looking at repairing or replacing the machine, because macOS expects some security information to be stored n that drive.

However, if there is "just" software corruption of the startup volume, there is Recovery Mode to deal with that.

-g wrote:

now it seems the rules have changed

You can boot off external drives on Apple Silicon Macs. That capability hasn't been completely taken away. But with Apple Silicon Macs, Apple introduced a new concept of "Ownership" above and beyond the "root vs Admin user vs regular user" distinction.

There are several articles on the web site of The Eclectic Light Company that go into things in much more detail than what I've seen in any Apple user documentation. (It's a photography Web site, but they also seem to have quite an interest in Macs, and to be a good source of technical information about them.)

The Eclectic Light Company – M-series Macs

Scroll down to the section on "External boot disks."

the Mac requires a functioning (whatever that means) internal SSD

Yes. It has to be working well enough for the Mac to access the security policy information stored in a "hidden" area on it.

to beat the horse further for clarity:

if the M-Series iMac internal SSD fails -- the machine is junk. period -- because the Mac requires a functioning internal integrated SSD before it will boot from an external source, like an external SSD boot macOS

If you're planning on overloading the virtual memory system to death – so much that you might burn out flash sectors – it might be advisable to prepare, and run from, an external startup SSD. That way, if excessive swap activity destroys the startup drive, it's "just" destroying an external drive that you can toss and replace.

However, most people aren't going to be in that sort of scenario. The machine's useful life will end long before their SSD burns out, barring an event such as the machine being fried by a lightning strike.

A downside to running off an external startup drive is that macOS will disable Apple Intelligence and Apple Pay.

How small is your drive

how much free unused space in on it

DriveDX (macOS) app will provide drive health and failure flags

AJA speed test app will provide read/write MBs

a proper thunderbolt external enclosure with NVMe M.2 SSD

will provide more fast space

and relieve a small SSD from filling up and turning flaky…

PS

the external can serve as the boot system drive

should the internal ssd fail

From your EtreCheck report:

❝Diagnostics Information (past 60 days):

2026-02-04 12:19:32 corespotlightd - High CPU Use (9 times)

First occurrence: 2026-01-28 12:21:06

Executable: /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/Metadata.framework/Versions/A/Support/corespotlightd❞

The corespotlightd process has been implicated in causing headaches for some Mac users in combination with Pages and documents saved on the iCloud drive.

https://discussions.apple.com/thread/255894068?sortBy=oldest_first

In my similar experience, the fix was to move the Pages docs, the ones that I usually keep open, from the iCloud drive to my Mac's local drive. This stopped corespotlightd from keeping the processor busy and stopped the hesitation and beachballing. Something to do with indexing, apparently.

I also noted the multiple VPN components that our friend, @KiltedTIm, spotted and I agree with their suggestion to remove them. Some light reading on the subject:

Private VPN's are Anything But Private and 

Security Risks: The Dangers of Using Free VPNs – eccu.edu.  

JohnTh wrote:

Thanks for all the info!

So, I'll be looking at replacing the machine in case of a hardware failure! Got it!

Seems to be a shame to throw the whole iMac away just because of a critical part that failed. But thats the way the world seems to be headed, something I'm not in agreement with btw. But ... here we are!

Integrated isn't always worse.

A plain M1 chip "is packed with … 16 billion transistors" (Apple unleashes M1 - Apple) . Should a critical one fail, the entire chip would need to be thrown away. Although the number of transistors varies from CPU to CPU, the same goes for Intel and AMD processors.

Then there was the ENIAC, the first general-purpose electronic digital computer. It "occupied a room 30 by 50 feet in size", "weighed 30 tons". and used over 18,000 vacuum tubes. The vacuum tubes were replaceable – a good thing, since "several tubes burned out almost every day, leaving ENIAC nonfunctional about half the time." Eventually engineers got this down to one tube every two days.

In order to get ENIAC to do anything, its operators had to rewire the machine, using plugboard wiring "and three portable function tables (containing 1,200 ten-way switches each)." This usually took weeks. And the machine was normally suffering vacuum tube failures every day, or every other day!

University of Pennsylvania – Celebrating Penn Engineering History: ENIAC

Wikipedia – ENIAC

Now we take it for granted that a CPU with 16 billion transistors – close to 90,000 times the number of vacuum tubes in the ENIAC – can load complex applications in seconds, and run for years without breaking down.

JohnTh wrote:

Have run First Aid via Disk Utility. There were some errors but reported ok.

FYI, Unfortunately the First Aid summary results can lie to the user. Even if the First Aid summary says everything is "Ok", click "Show Details" and scroll through the report to see if there are any unfixed errors or warnings. If there are, then run First Aid again until they are gone. If after several scans the errors remain, then run First Aid while booted into Recovery Mode.

If after several scans in Recovery Mode the errors remain, then you will need to erase the disk....how depends on whether the errors are on the "Data" volume or the hidden APFS Container.

• If the unfixed errors are for the "Data" volume, then a simple "Erase All Content & Settings" is sufficient for erasing the disk.
• If the unfixed errors are for the hidden Container, then you will need to use Disk Utility to erase the Volume Group. Afterwards you will need to reinstall macOS as well.

Here is an Apple article which contains instructions for both methods of erasing the disk:

Erase your Mac and reset it to factory settings - Apple Support

After either method you will need to restore your system from your backup.

If the errors are on the APFS backup snapshots, then they should not cause you any problems and will disappear as soon as macOS deleted those snapshots.

If the errors are on a snapshot identified as "update", then install the most recent macOS update patch and hopefully those errors will go away.

FYI, I'm not sure if this was mentioned within this thread, but you should run First Aid on the hidden Container. See the following Apple article for details:

How to repair a Mac storage device with Disk Utility - Apple Support

As far as I understand, this means that my internal hard drive is going to crash at some point in time.

If the errors & warnings are repaired, then everything will be fine.

If they cannot be repaired while booted into Recovery Mode, then the disk needs to be erased (see info in previous section).

If your file system keeps becoming corrupted after the errors/warnings are gone, then that could point to some sort of hardware issue.

Hopefully the iCloud + Pages connection mentioned by one of the other contributors is the cause of your iMac's performance issues.

JohnTh wrote:

I'm starting to see the spinning wheel often, when saving a Pages document or a Numbers spreadsheet. Have run First Aid via Disk Utility. There were some errors but reported ok. As far as I understand, this means that my internal hard drive is going to crash at some point in time.

No. But something is keeping the cpu busy when it shouldn't.

My question is: Can the internal drive be replaced on an iMac 2021 M1? Or do I need to replace it altogether for a new machine?

As our friends have posted, there is no replacing the internal storage of the M series Macs. When it fails, you will have to replace the computer, or the logic board at the very least.

I see nothing in the EtreCheckPro report that suggests a bad internal drive.

I do see two problems:

1) You have multiple VPNs that need to go as suggested by KiltedTim.

2) The iMac has not been restarted in over 30 days.

What I suggest is to:

1) completely uninstall the VPNs as per the developers directions.

2) restart in safe mode followed by a normal restart.

3) run and post a new EtreCheckPro report.

WOW THIS PLACE IS GREAT!

i am following you (D.I. Johnson)...

DISCLAIMER: i am slugging this out for information (don't rely on this writing)

i recently read where the Silicon Mac default PREVENTED booting from external drives

unless preconfigured in macOS Startup Security Utility

About Startup Security Utility on a Mac with the Apple T2 Security Chip - Apple Support

and that you could enable that permission booted into Recovery

and then boot off an external SSD system

now it seems the rules have changed -- if:

1. Recovery no longer provides users that external boot permission
2. the Mac requires a functioning (whatever that means) internal SSD

to beat the horse further for clarity:

if the M-Series iMac internal SSD fails -- the machine is junk. period -- because the Mac requires a functioning internal integrated SSD before it will boot from an external source, like an external SSD boot macOS

moreover:

this would seem to be applicable to all Macs with T2 chip and integrated SSD?

any further comment on my pros would be appreciated -- this information is central to my understanding of the Mac

+++++

the more i learn about the new stuff -- the more i like the old stuff...

JohnTh wrote:

Thanks for the clarification on hardware failure!

And yes, I'll uninstall all the VPN's which I didn't even know were there!

Be sure to remove their supporting files as well as the app itself. You can do that by  using the shareware app Find Any File to search for any files with a particular file name.  For VPN software you'd do the following search(es): 

1 - Name contains vpn

Any files that are found can be Option dragged from the search results window to the Desktop to get a copy of the file.

FAF can search areas that Spotlight can't like invisible folders, system folders and packages.  

Hi,

M1 Apple Silicon is called System on the Chip, it's contained CPU, GPU, RAM, and Storage.

If you need storage free space, you could connect external HDD/SSD.

I would be more inclined to

clone (or TimeMachine) the current to a fast external ssd

Erase the internal

reinstall macOS

use Migration Assistant to bring the clone back

what does DRIVE DX tell you?

If by "crash" you mean "hardware failure", then yes.

Otherwise, the "crash" could be software related.

You have multiple VPNs installed. get rid of them completely. They serve no legitimate purpose and do absolutely nothing to protect your privacy or secure your data.

They will interfere with normal operation and each other.