Best OS version for A1418 (iMac late 2015)?

[Chuchichan]

Hi,

I just reset an iMac (late 2015) 21.5 inch (A1418) with High Sierra.

Would High Sierra be the best option for this Mac or would you recommend a different one?

Thanks...

 

[velocityg4]

I'd just use Monterey. My 2015 MBP 13" runs it fine. As should your iMac. Do add an external SSD for the boot drive. If your iMac has a HDD. It makes a big difference in performance.

 

[Chuchichan]

Thanks. What's the easiest way to upgrade from High Sierra to Monterey?

 

[velocityg4]

Download and run the installer from the App Store. Just be aware. It'll probably be really slow without an SSD.

 

[iAppleOrchard]

Thanks. What's the easiest way to upgrade from High Sierra to Monterey?

System Prefrences > Software Update > Upgrade Now.

 

[Chuchichan]

I'd just use Monterey. My 2015 MBP 13" runs it fine. As should your iMac. Do add an external SSD for the boot drive. If your iMac has a HDD. It makes a big difference in performance.

Also, what type of external SSD would be best? I would have to reinstall the OS onto that SSD drive and then use the internal drive as basic storage? Would a thumb drive work? What size drive?

Thank you.

 

[velocityg4]

Also, what type of external SSD would be best? I would have to reinstall the OS onto that SSD drive and then use the internal drive as basic storage? Would a thumb drive work? What size drive?

Thank you.

No, thumb drives are horrible.

I’d get a Samsung 870evo and put it in an external USB 3 enclosure. Because the ready made Samsung T5 has horrible prices and NVMe is pointless over USB.

You could go with Thunderbolt. But I don’t think it’s worth the extra expense.

 

[Chuchichan]

Thanks for your reply. What type of enclosure would be needed? It seems like this would just plug into one of the USB ports on the iMac? The iMac late 2015 has USB 3.0 on all four ports?

 

[Chuchichan]

No, thumb drives are horrible.

I’d get a Samsung 870evo and put it in an external USB 3 enclosure. Because the ready made Samsung T5 has horrible prices and NVMe is pointless over USB.

You could go with Thunderbolt. But I don’t think it’s worth the extra expense.

Would this work? It seems like it has an enclosure?

Samsung 870 EVO 250GB SATA 2.5"(6.3cm) Internal Solid State Drive (SSD) (MZ-77E250)

870 EVO is the Samsung’s latest model of the world’s best-selling SSD series, with the latest V-NAND technology and the new MKX controller. 870 EVO proves why the EVO series has been the favorite choice among general users by showing the best in-class performance, committed reliability and conven...

www.amazon.com

Basically, it's a USB external drive? If so, would this Toshiba model work too?

Toshiba Canvio Basics 2TB Portable External Hard Drive USB 3.0, Black - HDTB420XK3AA

The Canvio Basics portable external hard drive allows you to collect your files and take them anywhere, offering high storage capacity, simple plug and play operation, and reliable performance. It features a compact design with a classic matte, black finish that is USB 3.0 and USB 2.0 compatible....

www.amazon.com

 

[velocityg4]

Would this work? It seems like it has an enclosure?

Samsung 870 EVO 250GB SATA 2.5"(6.3cm) Internal Solid State Drive (SSD) (MZ-77E250)

870 EVO is the Samsung’s latest model of the world’s best-selling SSD series, with the latest V-NAND technology and the new MKX controller. 870 EVO proves why the EVO series has been the favorite choice among general users by showing the best in-class performance, committed reliability and conven...

www.amazon.com

Basically, it's a USB external drive? If so, would this Toshiba model work too?

Toshiba Canvio Basics 2TB Portable External Hard Drive USB 3.0, Black - HDTB420XK3AA

The Canvio Basics portable external hard drive allows you to collect your files and take them anywhere, offering high storage capacity, simple plug and play operation, and reliable performance. It features a compact design with a classic matte, black finish that is USB 3.0 and USB 2.0 compatible....

www.amazon.com

No, that's just the SSD. But I was looking at prices and the NVMe SSD aren't any more expensive now. So you may as well get NVMe. The only possible benefit is more IOPS. Which could help. But there aren't any downsides. It is smaller and will make a good external for your next computer too.

SSD

SAMSUNG 980 1TB NVMe M.2 SSD - 3500MB/s Read Speeds, Turbowrite, For PC/Laptop/Gaming

Harness your PC's potential with the 980 SSD. Whether you need a boost for gaming or a seamless workflow for heavy graphics, the 980 is a smart choice for outstanding SSD performance — and it's all backed by an NVMe interface and PCIe 3.0 technology. Satisfy your need for speed with PCIe 3.0, usi...

www.amazon.com

Enclosure

SSK Aluminum M.2 NVME SATA SSD Enclosure Adapter, USB 3.2 Gen 2 (10 Gbps) to NVME PCI-E SATA M-Key/(B+M) Key Solid State Drive External Enclosure Support UASP Trim for NVME/SATA SSDs 2242/2260/2280

SSK Aluminum M.2 NVME SATA SSD Enclosure Adapter, USB 3.2 Gen 2 (10 Gbps) to NVME PCI-E SATA M-Key/(B+M) Key Solid State Drive External Enclosure Support UASP Trim for NVME/SATA SSDs 2242/2260/2280

www.amazon.com

That Toshiba is a HDD. It would defeat the purpose of the upgrade as HDD are slow.

Edit: The Samsung T7 has also come down since the last time I looked at it. You could get that for a prefab deal and not worry about putting the SSD in an enclosure. Since it is ready to go.

SAMSUNG T7 Portable SSD, 1TB External Solid State Drive, Speeds Up to 1,050MB/s, USB 3.2 Gen 2, Reliable Storage for Gaming, Students, Professionals, MU-PC1T0H/AM, Blue

SAMSUNG T7 Portable SSD, 1TB External Solid State Drive, Speeds Up to 1,050MB/s, USB 3.2 Gen 2, Reliable Storage for Gaming, Students, Professionals, MU-PC1T0H/AM, Blue

www.amazon.com

 

[Chuchichan]

Thank you. So, on this device, I would connect it to the iMac and reinstall the OS again and choose that ssd external drive as the install disk?

If it’s just holding the OS, would 256gb be good enough?

 

[gilby101]

If it’s just holding the OS, would 256gb be good enough?

I would get 1TB and put all my stuff on it - only slightly more expensive than 500GB. Wouldn't consider anything smaller.

Given that you will be using the USB-A ports on the iMac, a Samsung T5 might be cheaper and and only marginally slower than a T7 in a 5 Gb/s port. Get whatever is cheaper, prices seem to very wildly at present.

 

[Chuchichan]

I do have a SanDisk SSD X400 M.2 2280 256GB drive. If I get an M2 enclosure, would this be compatible with the iMac?

 

[gilby101]

I do have a SanDisk SSD X400 M.2 2280 256GB drive. If I get an M2 enclosure, would this be compatible with the iMac?

I would expect so. I guess it would depend on the enclosure. There is some risk.

 

[Chuchichan]

So, I tried installing High Sierra on the SanDisk 250GB drive and it failed. It says "MAC OS could not be installed on your computer. Failed to update preboot volume".

The boot usb is fine, because I can install it on the HDD. Could this particular SanDisk model be incompatible? Prior to installing High Sierra, I erased the drive and formatted it as APFS through disk utility.

 

[Fishrrman]

OP:

Everymac.com says the pre-installed version of the OS that came with the 2015 iMac is 10.11 "El Capitan", and that it's supported all the way up to 10.12 "Monterey".

My suggestions:
- If you have 32 bit apps, and need to keep using them, then you want to install OS 10.14 "Mojave". Mojave was one of Apple's best OS releases, in my opinion. It's the last release of the OS that can still run 32 bit software.
- If you DON'T have or need 32 bit apps, you might as well "take it all the way" up to OS 12 "Monterey".

Having said that...
Trying to assess "where you are right now"?

Did you say that you have High Sierra up-and-running on the internal drive?
and...
You'd like to get it running on an EXTERNAL SSD drive?
and...
That you have an m2 drive in an external enclosure? What KIND of enclosure?

I know that nvme blade SSDs in a USB3.1 gen2 enclosure work fine as external boot drives...
BUT...
Not sure about m2 blade SSDs in external enclosures.

In any case, I'd like to offer a different method for getting High Sierra onto the external SSD.

Instead of doing a fresh OS install, have you considered using either CarbonCopyCloner or SuperDuper to do a "clone" from the internal drive onto the external SSD?

Both of these are FREE to download and use for 30 days, this will cost you nothing.

I suggest SuperDuper, its interface is a little easier if you've never used these apps before.

Just start SD, use your internal drive as the source, use the SSD as the target, and let SD do the rest.

It will even erase and prep the external drive before cloning.

See if this works.

When done, before you reboot, go to the startup disk pref pane.
Enter your password to unlock it, then set the SSD to be the boot drive.
Then, reboot.

How does that go?

 

[cairnwalker]

OP:

Everymac.com says the pre-installed version of the OS that came with the 2015 iMac is 10.11 "El Capitan", and that it's supported all the way up to 10.12 "Monterey".

My suggestions:
- If you have 32 bit apps, and need to keep using them, then you want to install OS 10.14 "Mojave". Mojave was one of Apple's best OS releases, in my opinion. It's the last release of the OS that can still run 32 bit software.
- If you DON'T have or need 32 bit apps, you might as well "take it all the way" up to OS 12 "Monterey".

Having said that...
Trying to assess "where you are right now"?

Did you say that you have High Sierra up-and-running on the internal drive?
and...
You'd like to get it running on an EXTERNAL SSD drive?
and...
That you have an m2 drive in an external enclosure? What KIND of enclosure?

I know that nvme blade SSDs in a USB3.1 gen2 enclosure work fine as external boot drives...
BUT...
Not sure about m2 blade SSDs in external enclosures.

In any case, I'd like to offer a different method for getting High Sierra onto the external SSD.

Instead of doing a fresh OS install, have you considered using either CarbonCopyCloner or SuperDuper to do a "clone" from the internal drive onto the external SSD?

Both of these are FREE to download and use for 30 days, this will cost you nothing.

I suggest SuperDuper, its interface is a little easier if you've never used these apps before.

Just start SD, use your internal drive as the source, use the SSD as the target, and let SD do the rest.

It will even erase and prep the external drive before cloning.

See if this works.

When done, before you reboot, go to the startup disk pref pane.
Enter your password to unlock it, then set the SSD to be the boot drive.
Then, reboot.

How does that go?

I purchased a Samsung T7 SSD for this purpose and used SuperDuper to make a bootable copy of the internal HD from my late-2015 iMac running Monterey. (In fact, I did this several times) Each time I try to boot the iMac from the SSD, it gets about halfway through and just 'hangs'. No error messages. Has anyone actually verified booting from an external SSD? Comments or suggestions welcome.