Can I use my late 2015 iMac as external monitor and memory for a 2024 M2 Mac mini?

yavor192 Said:

"Can I use my late 2015 iMac as external monitor and memory for a 2024 M2 Mac mini?"

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Using a 2015 Mac for Memory and External Monitor:

No. Not for Memory, nor as an external monitor: Use your iMac as a display with target display mode - Apple Support

Re: “iMac can be use for any MacBooks only it doesn’t matter how old is the iMac because for MacBooks as external minitogg to works perfectly fine “

Incorrect. The issue here is that Late 2015 iMacs do not support Target Display Mode, and the restrictions Apple has placed on newer Macs keep them from using any iMac as a Target Display.

Given the right combination of old Macs, there is no problem with having one desktop Mac being the source of the video displayed on another desktop Mac (an iMac) running in Target Display Mode. The source of the video does NOT have to be a MacBook.

yavor192 wrote:

Actually Target dispaly mode DOES exist in my mac's menu

Target Display Mode was never a menu option. I don't know what you're seeing, but it isn't Target Display Mode. Apple discontinued Target Display Mode in Late 2014 when the first 27" 5K Retina iMacs came out, so your iMac definitely does not support being a Target Display. (When running Catalina or earlier, your iMac would be able to use another old iMac as a Target Display.)

The problem of slowness on the iMac it’s because those iMac came with a mechanic HDD and only 8 gigs of ram , that iMac has a good 3.3 GHz processor but if you upgrade the ims with SSD and add 16 gigs let me tell you that you won’t see slowness anymore , I have the same iMac and I did the upgrade and runs flawlessly and also I did install windows 10 on using bootcamp and runs perfectly go to ifixit.com of YouTube and find the tutorial and learn how to upgrade your iMac I can asure you that you won’t regret it investing some money buying a 1tb SSD and the memory ram just make sure getting the real ones

yavor192 Said:

"Can I use my late 2015 iMac as external monitor and memory for a 2024 M2 Mac mini? [...]I think of buying a mac mini but would like to use it with my old mac as a display only because they are no longer selling the big 27'' imac-s. Can I do this and how should I connect them if yes?"

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As for Upgrading...

Your Mac is almost a decade old. So, take this as a good reason to upgrade. IMPORTANT: Prior to ridding of it, perform as instructed here, including the Time Machine Backup creation and iCloud logout: What to do before you Sell, Give Away, Trade in, or Recycle your Mac - Apple Support

Troubleshooting Lagging Mac:

A. Try Safe Mode:

In Safe Mode, login items do not run, and corrupt system files(i.e. caches) are intentionally reset as a way to fix issues

1. Boot: in to Safe Mode: [Hold Down: shift key upon boot].
2. Log in: as same user
3. Wait: 30 seconds
4. Restart; your Mac
5. Log in: as same user

B. See if your Hard drive is Failing:

What to Try:

• Verify your Drive: Repair your Disk in Disk Utility - Apple Support
• Go Here: If your Mac Starts Up to an Apple Logo or Progress Bar - Apple Support
• Perform the following in Recovery Mode:

1. Boot: into Recovery Mode. Go Here:  How to Use Safe Mode on your Mac- Apple Support
2. Select: Disk Utility
3. Select: the Drive
4. Click: First Aid button

C. Remove Login Items:

While in Safe Mode, remove all of your Login Items, and then restart the Mac.  Go Here: Change Users & Groups Login Items Preferences on Mac - Apple Support

Reading all the answers I can see your question wasn’t answered , iMacs are desktop computers as the Mac mini too you can’t use an iMac as monitor for a Mac mini because boths are desktop computers, iMac can be use for any MacBooks only it doesn’t matter how old is the iMac because for MacBooks as external minitogg to works perfectly fine

yavor192 Said:

"Which operation system would be most suitable for this old machine, now I run Big Sur 11.7.10 and I'm afraid of going to a newer version not to slow down the computer futher?"

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Thank you or the followup reply.

Big Sur, is indeed the latest you can go:

macOS Big Sur 11 Hardware Requirements - Apple Support

For reference...

Determining which Update(s) will Install:

I. Verify Compatibility:

A. Start Here: Learn About Compatibility and how to Identify your Specific Mac Model - Apple Support

B. How to Verify:

I. Reveal your Model:

What is the Model of your Mac? To find out...

1. Go to: Apple menu
2. Click: About this Mac
3. View: Second Line-Down

then...

II. Compare the Results:

See if the Model you found is shown here:

• macOS Sonoma is Compatible with these Computers - Apple Support
• macOS Ventura is Compatible with these Computers - Apple Support
• macOS Monterey is Compatible with these Computers - Apple Support
• macOS Big Sur 11 Hardware Requirements - Apple Support
• macOS Catalina 10.15 - Hardware Requirements - Apple Support
• macOS Mojave 10.14 - Hardware Requirements - Apple Support
• macOS High Sierra 10.13 - Hardware Requirements - Apple Support
• macOS Sierra 10.12 - Hardware Requirements - Apple Support
• OS X El Capitan 10.11 - Hardware Requirements - Apple Support
• OS X Yosemite 10.10 - Hardware Requirements - Apple Support

III. If Compatible:

Back Up your Mac First:  Be certain you Create a Time Machine Backup of your Mac, so that way you can have something to restore your Mac from, should anything go wrong with the reconfiguration.

yavor192 Said:

"Which operation system would be most suitable for this old machine, now I run Big Sur 11.7.10 and I'm afraid of going to a newer version not to slow down the computer futher?"

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Thank you for the followup reply.

When Transferring to a New Mac:

Use QuickStart:

Rather than transferring everything over manually, your could use QuickStart. I can be a pocket save, not having to purchase apps, all over. However, some apps (i.e. MS Office) do not permit older versions on newer devices, in which case, you'd have to purchase a new license, if incapable with one another.: Learn More here: Use Quick Start to Transfer Data to a new iPhone, iPad, or iPod touch - Apple Support

TheLittles wrote:

When Transferring to a New Mac:

Use QuickStart:

Rather than transferring everything over manually, your could use QuickStart. I can be a pocket save, not having to purchase apps, all over. However, some apps (i.e. MS Office) do not permit older versions on newer devices, in which case, you'd have to purchase a new license, if incapable with one another.: Learn More here: Use Quick Start to Transfer Data to a new iPhone, iPad, or iPod touch - Apple Support

It sounds like QuickStart is for the iPhone, iPad, and iPod touch.

I believe that the OP would want to make an up-to-date backup of the old Mac on an external drive, using Time Machine, Carbon Copy Cloner, or SuperDuper! The OP could then connect the drive to the new Mac and point Migration Assistant at the Time Machine backup or bootable clone backup ("startup disk").

Ozzie1910 wrote:

Reading all the answers I can see your question wasn’t answered ,

Actually, it was answered correctly in the very first reply to the question.

Servant of the Cats Said:

“It sounds like QuickStart is for the iPhone, iPad, and iPod touch.[…}”

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You’re correct. And the three apps you’ve mentioned will do just fine.