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Can I Use iMac As Monitor For Mac Mini ?

My imac 2017 has an issue.first of all Ventura is the last Os that will work on this hardware according to apple.

then there is a problem.when i mac is on sleep ,sometimes doesn't wake up.i disconnect a usb hub and the ethernet but still no reaction.

i force to end its operation by the energy button.and then i restart my imac and everything is fine.also in random timelines i hear a gling-metal noise like 2 coins are dropping into a slot which i read here that might be the hard disc going to failure.

so i was thinking of saving the screen of my imac and use it for a new mac mini .if its possible to connect the 2 devices together and work.

i found this article.its about a connection between an imac 's screen and a pc. and i thought that if it really works with a pc then it should work with a mac mini.


[Edited by Moderator]

iMac 21.5″, macOS 13.7

Posted on Jan 16, 2025 1:16 PM

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Question marked as Top-ranking reply

Posted on Jan 16, 2025 1:30 PM

I'm unfamiliar with that third-party app.


The traditional Target Display Mode won't work here: Use your iMac as a display with target display mode - Apple Support — your iMac is too new.


Your gear is also too old for AirPlay to Mac: Continuity features and requirements for Apple devices - Apple Support


If your iMac hardware is failing, whether the hard disk drive or something else, it's anybody's guess what happens.


Diagnostics won't find transient errors, but might find some errors: Use Apple Diagnostics to test your Mac - Apple Support


If the iMac hard disk is failing, a potential workaround: How to Setup and Use an External SSD as your startup disk… - Apple Community

33 replies
Question marked as Top-ranking reply

Jan 16, 2025 1:30 PM in response to macman1585

I'm unfamiliar with that third-party app.


The traditional Target Display Mode won't work here: Use your iMac as a display with target display mode - Apple Support — your iMac is too new.


Your gear is also too old for AirPlay to Mac: Continuity features and requirements for Apple devices - Apple Support


If your iMac hardware is failing, whether the hard disk drive or something else, it's anybody's guess what happens.


Diagnostics won't find transient errors, but might find some errors: Use Apple Diagnostics to test your Mac - Apple Support


If the iMac hard disk is failing, a potential workaround: How to Setup and Use an External SSD as your startup disk… - Apple Community

Jan 17, 2025 4:14 AM in response to macman1585

macman1585 wrote:

so if hard disc fails then my imac can still work with an external ssd?


Maybe, maybe not. I ran an old iMac for a long time off an external SSD, with the internal HDD ejected and spun down. There came a time when the internal hard drive started spinning up by itself anyway. Eventually the Mac suffered several crashes, which could well have been the result of the internal hard drive throwing errors despite not being in use. Then the external SSD got corrupted and became useless as a boot drive.


I may try to resurrect that Mac at some point, to run old 32-bit applications, but after getting nearly 14 years of use out of it, it seemed like time to move on.


how about the OS..Ventura is the last one on it and from what i read it will be outdated from updates ,in about 2-3 years meaning my imac wont work properly after these 2-3 years ,meaning get a new one.so is it worthy to give an extension of life to my imac investing to an external ssd?


No, it doesn't mean that your Mac "won't work properly after 2–3 years." It does mean that after 2-3 years, you will find it harder to get new applications that are compatible with that Mac … and you won't be getting security updates. The best time to buy/get the applications that you need is while your Mac is running one of "the most recent three", but there are some applications (like Firefox and LibreOffice, whose current versions only require Catalina or better) that you may be able to add to an old Mac to make it useful longer.


i think that with a new ssd i cant have the latest OS even if i wanted to bcs my hardware can't support it anymore.or am i wrong?


Adding a new SSD will not change the maximum version of macOS that your Mac supports. It won't allow you to install Sonoma or Sequoia.

Jan 18, 2025 10:23 AM in response to macman1585

First, don't sleep the iMac. Just have the screensaver go on and after a set time go blank. Do not sleep.


Also is the hub self powered? If not that may be why you're having problems, i.e. overloading the current draw on the port the hub is plugged into. Solution: get a self powered hub.


Have you installed and run any "cleaning", "optimizing", "speed-up", anti-virus or VPN apps on your Mac? If you have, that may be part of the problem.


Do you have a Fusion drive?


I have a 27" 2017 iMac but with a SSD boot drive. It runs fine on the latest Ventura.


For an excellent view of your system and hardware's health do these two things and post the results in your reply:


1 - download and run DriveDX (the free version is sufficient.

2 - download and run Etrecheck.  Again, the free version is sufficient.


Copy the report as shown in this animated screenshot



and use the Additional Text button to paste the report in your reply.



Then we can examine the report and see if we can determine the cause of the problem.


Jan 18, 2025 6:05 AM in response to macman1585

macman1585 wrote:

just remembered , my nephew has a 2011 imac which failed from motherboard. is its hard disc alive? its been 4 years since it has been used.will it fit to my 2017 imac if i try? well not me ,but a tech guy.


You can use a 2011 iMac as a Target Display for a 2017 iMac if

  • Both are working
  • The 2011 iMac is running High Sierra or earlier (which it will be – it can't run anything later)
  • The 2017 iMac is running Catalina or earlier
  • You make a Thunderbolt connection (e.g., with the aid of an $50 Apple Thunderbolt 3-to-2 adapter and a $30+ Thunderbolt 1/2 cable)


2017 iMacs are able to run Ventura, so unless you were already deliberately holding one back on a pre-Catalina OS (to run 32-bit software), you'd be crippling the 2017 iMac by downgrading from Ventura.


$80+ on specialized Thunderbolt connection hardware (that you're likely to never use again) is a good fraction of the cost of a new standalone monitor that would use less electrical power, be more convenient to operate, and be more likely to survive for another 10 years.


Use your iMac as a display with target display mode - Apple Support

Jan 19, 2025 9:21 AM in response to macman1585

macman1585 wrote:

no ,i meant if i can replace my hard disc when/if it fails with the 2011 imac's one.i dont know if its possible to pull it out and place it in mine's hard disc place.

by the way how do we know if a hard disc is failing? which are the most common symptoms? except that gling noise they told me it could be


Better to swap an old and sketchy hard disk with a newer or new SSD.


Extracting components from most of the iMac 21.5” models is a project.


Look up some You Fix It disassembly videos, and decide for yourself what repairs and upgrades you want to try.


If the existing 2011-old HDD is still working, keep backups, I’d run it into to failing, and replace it with an SSD. This if the goal here is to spend no money on the gear, and the backups can be trusted. (Otherwise: data loss ahead.)


Hard disks fail in various ways, ranging from getting slow, to showing SMART errors, to instant failures.


SMART isn’t overly useful for predicting many sorts of failures. It misses a whole lot of impending failures.


Unless you want to develop skills at disassembly and re-configuring and re-purposing, I’d stick to using external storage. Expect to break pieces while learning, too. Even after. Decade-old clips can just disintegrate.


Or source yourself some less-old gear, as that gets you incrementally newer and better gear, as compared with that 2011, for instance.

Jan 19, 2025 10:19 AM in response to macman1585

To determine if the drive is failing download the free version of DriveDX, run it and post the results in you reply.


Also, to make sure the problem isn't due to 3rd party software run Etrecehck and post the report as I mentioned in my previous post.


It would be difficult to get into the 2017 iMac and replace its existing SSD with the old SSD. If it was like my earlier iMac, it had magnets holding the screen on instead of adhesive as the 2017 has, I think you'd be better served by getting a Thunderbolt external SSD, install Ventura on it and migrate your user data via Migration Assistant and your Time Machine backup of the 2017.

Jan 19, 2025 11:46 AM in response to macman1585

macman1585 wrote:

…also i have never run any of these diagnostic programs not even have installed any of them.i wanted to but opinions vary especially about etrecheck. i never had any serious problem to try them.


Etrecheck report avoids playing a game of thousands of questions.


Same for DriveDx.


now about the hub. i am not sure what you mean about a self powered hub.

If it plugs into a power socket, it is a powered hub.


If the hub does not plug into, it is a bus-powered hub.


The former usually has the ability to provide more power to connected devices than the host port can provide.


…it is connected with a usb cable to the imac port and with a power cord to the ups plug .


That would be a powered hub. Three hubs and lots of connected devices can be less than stable.


about the sleep mode.oh man, this is a vary debatable subject on the Internet community.many are for it and many against it. some told me ,do you switch off your phone, then why do that to your pc? and such opinions.that metals are doing a hard job trying to turn on the mac and that causes problems to hardware.some others say that in sleep mode imac uses more power e.t.c.

Do ypu

i dont know which is good for my hardware


The default power-management settings provided by Apple are usually a pretty good choice.


The downside with hard disk configurations is that powering down and powering up wears those, which is where that keep-spinning suggestion usually arises with old hard disks.


Pending the Etrecheck and the DriveDx reports, whether there are hard disks drive issues is unconfirmed.


i dont really know what you mean ''to go blank'' .what is that?


A display can be powered down, or can be left powered up and running some screensaver.


The suggestion was to power down the display, which can be configured in System Settings.

Jan 19, 2025 12:15 PM in response to macman1585

MrHoffman answered your questions as well as I could. Etrecheck is one of the best diagnostic apps available for Macs. Its report is totally anonymous and, as MrHoffman has already mentioned, prevents us from playing the game of 20 Questions. We wouldn't recommend them if they weren't totally safe.


But as they say, you can lead a horse to water but can't make him drink. So the next step is up to you as it's your Mac.

Jan 20, 2025 7:14 AM in response to macman1585

macman1585 wrote:

The suggestion was to power down the display, which can be configured in System Settings.
i tried to find the power down the display setting but there isnt on written like that in my ventura system settings.
is it the:
system settings> energy (the yellow button with the bulb) > turn on(activate) power nap ?

do you know the exact path in ventura? i am still learning that OS.


I'm running Ventura. The closest thing I can find is this". Run System Settings. Select Displays. Press the Advanced… button. In the dialog that comes up, there will be an Energy section, with a switch to "Prevent automatic sleeping when the display is off."


On my Mac, this switch is disabled (the setting can't be changed), and in the "Off" position. I don't see any display-related controls in the Energy Saver settings.


But maybe if I was using an iMac or a Mac notebook which had a built-in screen, there would be some extra controls, or that switch would be one that I could actually toggle.

Jan 21, 2025 12:27 PM in response to macman1585

If we are talking about external drives getting disconnected when you put the Mac to sleep, and then wake it up, the issue is with putting the Mac to sleep.


Old versions of macOS used to have controls to put hard drives to sleep, and I believe (though I'm not sure) that you could use those as long as you didn't let the computer (and its ports) go to sleep.


Something about putting the computer and ports to sleep, then waking it up, seems to be involved in unexpected disconnection of external drives. Though it's not clear if the issue is with the computer, with certain external drive enclosures, or both.

Jan 22, 2025 4:29 PM in response to macman1585

macman1585 wrote:

energy (orange box with white bulb)> put hard disk in sleep mode whenever is possible, I DEACTIVATED THAT
> activate power nap , I DEACTIVATED THAT
> wake up from sleep mode for internet access, i left it ACTIVATED

displays> prevent automatic sleep mode when screen is deactivated, I DEACTIVATED THAT


In other words, you told the computer it was OK to put the entire computer to sleep when the screen was not in use?


Set sleep and wake settings for your Mac - Apple Support (desktop computer section):

  • Stop automatic sleeping when the display is off: Turn on “Prevent automatic sleeping when the display is off”.


conclusion.with the hub disconnected ,certainly that wasn't the cause. sleep mode no more, so that wasn't the cause either.


To the contrary, you told the computer that it was OK to go to sleep.

Jan 16, 2025 7:49 PM in response to Servant of Cats

Servant of Cats wrote:

…If this thing is squeezing a 5K signal over a plain USB-C (DisplayPort Alt Mode) connection, what changed, and how would that affect Mac compatibility?


Mac mini (2024) - Tech Specs - Apple Support


Mac mini 2024 with M4 Pro supports USB-C DP 2.1, and 8K 60 Hz HDMI 2.1, among other options, and other Mac models.


Jan 16, 2025 7:16 PM in response to MrHoffman

I didn't mean physically. I know what a cable with USB-C connectors on both ends is.


I mean in terms of bandwidth, since Macs have traditionally supported connecting

  • A single monitor with a resolution of up to 4K @ 60 Hz over USB-C (DisplayPort Alt Mode)
  • A single monitor with a resolution of up to 6K @ 60 Hz, or two monitors with resolutions of up to 4K @ 60 Hz, over Thunderbolt 3 (a.k.a. USB-C (Thunderbolt Alt Mode))


If this thing is squeezing a 5K signal over a plain USB-C (DisplayPort Alt Mode) connection, what changed, and how would that affect Mac compatibility?

Jan 21, 2025 12:40 AM in response to MrHoffman

MrHoffman wrote:

I’d try some variation of the following command-line command, given it seems macOS 15 removed some settings from the GUI here:
sudo pmset -a displaysleep 5 sleep 15

That should cause the display to sleep after five minutes, and the Mac to sleep after fifteen minutes, regardless (-a) of the current power source. I might add -u with different settings when running on UPS. If there’s a UPS.

I don’t have a macOS 15 system handy to test.

wait,didnt you suggest the imac NOT be in sleep mode?


First, don't sleep the iMac. Just have the screensaver go on and after a set time go blank. Do not sleep.

i am confused.whats the difference between blank and sleep mode ,first you suggested to go blank and now you suggest to go to sleep mode.

so sleep mode = blank = black screen, like sleep mode does?


in lock screen setting there is an prion menu that let us choose :


  • how minutes after the screen saver will begin when screen is inactive (this is set by me to 5')
  • how many minutes after the screen will be deactivated when it is inactive (this is set by me to 10')


is it this what we are looking for? the blank display?or is this the sleep mode?


p.s. i disconnected the powered hub. imac runs fine and wakes up from sleep mode or blank screen -i hope we clear this out-with no issues.but lets give it some time to test it ,to see if it freezes again and doesn't wake up with the press of a key like it should do.


Can I Use iMac As Monitor For Mac Mini ?

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