Using IMAC 5K Late 2015 as Monitor for MacBook Pro

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Level 1

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Using IMAC 5K Late 2015 as Monitor for MacBook Pro

Don't know if this is possible but I want to use my IMAC 27" 5K Late 2015 as a monitor for my MacBook Pro late 2017. My IMAC currently runs very slow and freezes often. I have a 13" MacBook Pro that works great. I want to use the MacBook Pro as my main computer but don't want to use the screen and keyboard. I would like to use the IMAC 27" 5K as the monitor for the laptop and hook up a keyboard and mouse to use. The only purpose for using the MacBook Pro would be as the hard drive. Would like to use the IMAC screen and my secondary screen set up as the monitors. I would also like to use the IMAC camera and speaker and mic as well. Is this possible ?

iMac 27", macOS 10.15

Posted on May 19, 2020 1:41 PM

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Answer 1

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josephbronx Author

Level 1

16 points

May 19, 2020 8:50 PM in response to rkaufmann87

Thank you for this info. One last question. Would you suggest buying a new iMac since this one runs slow or just getting a docking station and using my MacBook Pro as the main computer with two monitors hooked up to the docking station. The MacBook Pro runs a lot faster than the iMac I have.

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Answer 2

josephbronx Author

Level 1

16 points

May 19, 2020 8:51 PM in response to den.thed

Thank you for this. I am just wondering since I have many issues with my IMAC 5K late 2015 I am wondering if I should buy a new IMAC or get a docking station and hook up to my MacBook Pro which has no problems and runs smoothly.

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Answer 3

Old Toad

Level 10

207,199 points

May 28, 2020 2:06 PM in response to josephbronx

I would not purchase a new iMac without determining what is causing your current Mac to be so slow.

Download and run Etrecheck. Etrecheck is a diagnostic tool that was developed by one of the most respected users here in the ASC and recommended by Apple Support to provide a snapshot of the system and help identify the more obvious culprits that can adversely affect a Mac's performance.

Copy the report

and use the Add Text button to include the report in your reply. How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report

IMPORTANT:

Before running Etrecheck assign Full Disk Access to Etrecheck in the Etrecheck's Privacy preference pane so that it can get additional information from the Console and log files for the report:

Then we can examine the report and see if we can determine what might be causing the problem.

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Answer 4

Androish

Level 8

39,469 points

May 19, 2020 1:46 PM in response to josephbronx

No the 2015 model of iMac does not feature this option.

Earlier models had something called target display mode, but it was fazed out.

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

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Answer 5

rkaufmann87

Level 10

140,142 points

May 19, 2020 10:15 PM in response to josephbronx

What do you mean you have issues with the 2015 iMac. Please do the following:

Please navigate to the Mac App Store or navigate to www.Etrecheck.com and download the free version of EtreCheck. Once you have you downloaded the app and installed it, please run the report and save it. This report will help us get a good idea what has been installed on your system and help us be able to diagnose what may be wrong.

When you have your report, you can attach it when you reply to this message and we can then review it and help you determine what is needed to get your system running well again.

For instructions on how to download your EtreCheck report and attach it to your reply to this message please click https://discussions.apple.com/docs/DOC-250000211

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Answer 6

den.thed

Level 9

76,768 points

May 19, 2020 1:46 PM in response to josephbronx

Nope, the Late 2015 iMac does not support being used as a display.

see > Use your iMac as a display - Apple Support

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Answer 7

josephbronx Author

Level 1

16 points

May 19, 2020 8:53 PM in response to Androish

Thanks for the info. I am wondering since I have many issues with my IMAC 5K late 2015 if I should buy a new iMac or purchase a docking station and use my MacBook Pro as the main computer with two monitors hooked up to the docking station instead. the MacBook Pro runs smoothly.

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Answer 8

josephbronx Author

Level 1

16 points

May 19, 2020 9:28 PM in response to den.thed

Yes Thank you I understand that. But my question is should I just replace my IMAC with a newer one since I have issues with it or buy a docking station and use my MacBook Pro as the main computer and hook up my Samsung Monitors to the docking station and just abandon the IMAC all together.

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Answer 9

josephbronx Author

Level 1

16 points

May 28, 2020 1:34 PM in response to rkaufmann87

So my issues with my IMAC is it runs very slow. To open an application or document or even go to a webpage it takes a minute or two to open. Its not my internet speed because I have Verizon Fios and updated to 1GB of speed. Besides its not just web searching that is slow. As I said to open a simple app like Adobe Acrobat takes about a minute or two to open. To open apple Message Icon also takes long to load. I installed the app Etrecheck like suggested. It informed me that the Runaway process is using a large percentage of CPU. The Heavy CPU Usage also indicated some processes are using an unusually high amount of CPU and Software performance problems indicated that software seems to be causing performance problems. It also indicated that there were unsigned files and EtreCheck took an unusually long time to run. There were 32bit apps on this machine and kernel extension that may not work in the future. Finally it also indicated that the machine has sharing services enabled that could be a security risk. It prompted me to run Activity monitor which I did and I noticed that kernel_task was using 498.4% of CPU everything else was under 50%. At one time Final Cut Pro was running at 74.5% CPU and System_Profiler was running at 113.2% CPU

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Answer 10

BDAqua

Level 10

238,697 points

May 28, 2020 6:57 PM in response to josephbronx

Likely your biggest problems is Sophos, I'd uninstall it per their directions.

Next having both OneDerive & DropBox both auto start in Login items is likely another slowing factor, I just run them wehen I'm not going to be doing something.

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Answer 11

josephbronx Author

Level 1

16 points

May 28, 2020 7:24 PM in response to BDAqua

Thank you for the follow up. I know it's not Sophos because I installed this app a few weeks ago but have been having this problem for several months before I installed. I will remove the auto start and see if this helps. Thanks

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Answer 12

josephbronx Author

Level 1

16 points

May 28, 2020 5:57 PM in response to Old Toad

EtreCheck Report

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Answer 13

rkaufmann87

Level 10

140,142 points

May 19, 2020 1:55 PM in response to josephbronx

Nope, not possible. Target Display Mode (TDM) was discontinued beginning when Retina Imacs became available in 2015. If your MBP needs an external display your bet option is to buy one.

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