Can I Use iMac As Monitor For Mac Mini ?

If that Mac was working, you could use it as a second screen using Luna Display (Astropad). That workaround is not as good as a hardware connection to a real display – and the Astropad site itself says that Luna Display is not suitable for high-motion content such as from gaming or video editing.

However, if the iMac is failing, there's no guarantee that it would even work with Luna Display. It has bo be able to run, to run the Luna Display software.

It sounds like you need to buy a real monitor for the new Mac mini.

I know of only three 27" 5120x2880 (5K) monitors on the market – the Apple Studio Display, one from LG, and one from Samsung. The LG and Samsung ones list for more than $1000, but often sell for a street price of about $800 to $950, making them less expensive than the $1600+ Studio Display.

If you're willing to compromise a bit on the resolution, there are plenty of 27" 3840x2160 (4K) monitors – and you can get some with IPS panels and near-100% coverage of sRGB for as little as $300 - $350.

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

Realistically, no. Even if you could, it would require the iMac to be in working condition. It sounds like it's not long for this world...

Just go buy a monitor.

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.

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.

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.

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

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.

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.

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.

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.

Do keep current backups obviously, as a failing hard disk degrades into doom.

Servant of Cats wrote:

...I know of only three 27" 5120x2880 (5K) monitors on the market – the Apple Studio Display, one from LG, and one from Samsung...

ASUS ProArt PA27JCV, and the just-announced BenQ PD2730S, too.

MrHoffman wrote:

Servant of Cats wrote:

...I know of only three 27" 5120x2880 (5K) monitors on the market – the Apple Studio Display, one from LG, and one from Samsung...

ASUS ProArt PA27JCV, and the just-announced BenQ PD2730S, too.

It's good news that more are coming out.

I wonder how that Asus ProArt PA27JCV connects. The description mentions USB-C (DisplayPort) but doesn't say anything about Thunderbolt. The BenQ PD2730S connects via Thunderbolt 4.