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R2018b / R2019a runs very slow on macOS 10.14

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Edit: For me, the problem presists on R2019a.
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Hi everyone,
I am using macOS 10.14 (Mojave) and just upgraded the MATLAB to R2018b yesterday and found a very strange problem. The editor runs EXTREMELY slow on my system and often freezes. When I click on somewhere on the editor or scrolling the view it usually takes 1-2 secs to response.
However, the strange point is, the problem only occurs when the MATLAB window is displayed on my external monitor. When I move the window to the macbook's internal monitor, everything is normal. And, the problem does not show on some specific files. I don't know if there are any features of those file, but if I make copies of those files, the problem may shows on the copies again.
I am not sure if it is a problem of MATLAB or my OS. How is the R2018b running on your systems?
Walter Newsome
Walter Newsome on 25 Jan 2021
Yes, I had the same issue. Disabling Magnet fixed it
yangpeng zhang
yangpeng zhang on 11 Mar 2021
Got it! Just uninstall Matlab and remain magnet, then you can resolve this problem.hhhhhh

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Accepted Answer

Kris Fedorenko
Kris Fedorenko on 3 Oct 2018
Edited: Kris Fedorenko on 3 Oct 2018
There were instances of similar behavior in R2018b caused by the Magnet app. Turning it off should resolve the issue. Alternatively, you should be able to use keyboard shortcuts with no delays.
Nigel Davies
Nigel Davies on 23 Dec 2020
Disabling Magnet also worked for me, r2021a prerelease and r2020b, MacBook Pro with Apple Silicon M1, macOs Big Sur.
Kaito Kusumoto
Kaito Kusumoto on 8 Jan 2021
Unbelievable!! Thanks a lot. This helped me.

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More Answers (26)

Felix Reuen
Felix Reuen on 1 Oct 2018
Edited: Felix Reuen on 1 Oct 2018
I've got the same problem. Matlab R2018b is very slow, but only when I'm editing scripts. It takes like a second for the courser so appear after I clicked at a point in the code. As far as I know, it occurs on the internal monitor, haven't tested a external one yet. The benchmark results are very bad, I'm always between 7th and 9th place, although it's a i7, 16gb ram macbook pro with iOS 10.13.
Harry Chellis
Harry Chellis on 3 Oct 2018
Same here, it is unusable on macOs Mojave. Multiple seconds delay in selecting a line of text and/or scrolling.
Olivia Cracchiolo
Olivia Cracchiolo on 9 Oct 2018
I am having the same issue and I don't even have any window snapping apps installed. I can't even plot my data, suggestions?

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Nicolas B
Nicolas B on 10 Apr 2019
Edited: Nicolas B on 10 Apr 2019
Also experiencing this issue.
Matlab slows down to a crawl as soon as I open the help window or plot a figure.
Running macOS Mojave 10.14.4 on a 16gb 2015 Macbook Pro.
Disabling Source Control integration and incrasing Java Heap Memory size twofold does not help.
I do not have any windowing app.
The problem is the same regardless of the monitor (internal/external).
Darcy Cordell
Darcy Cordell on 18 May 2021
Same for me. All the solutions online talk about window snapping apps but I do have one installed.

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Danni Brito
Danni Brito on 22 May 2019
Open the Matlab interface, go to the Magnet icon and click it, press on "Ignore Matlab", everythink should be normal now.
Marcel Goldschen-Ohm
Marcel Goldschen-Ohm on 24 May 2019
Thanks so much to whomever developed this solution. Kudos!

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Shen Zhao
Shen Zhao on 2 Dec 2018
I use macOS 10.14.1 and Matalb 2018b.
The same thing happens for me. Mine is even worse. All of the Matlab app crashes for me.
It is really annoying than just being sluggish in Matlab. I originally thought it is due to java. I uninstalled java completely but then these things still happened. Then I completely reinstalled macOS and install software. Here comes the interesting things.
With fresh macOS. Af first, everything finally works. I can use Matlab app like classification app learner etc. But later when I install other softwares, the annoying things happen again!!! So annoying!!!
Then I find this question, some app conflicts with Matlab 2018b.
I do not have magnet but some other service ran in the background. Then I end the process one by one and check whether it works. Then I find, when I kill the "popclip" process, finally everything works perfect now!

Chris Rorden
Chris Rorden on 7 Feb 2020
I had issues with the GUI of some popular MATLAB tools freezing: the checkboxes of dicm2nii and the file selection dialogs of SPM. I do not have any of the tools described here (Magnet, Moom, PopClip, HyperDock), so I was perplexed. I discovered my issues could be resolved if I disable the "Zoom" option in the 'Accessibility' of the System Preferences (shown enabled by the blue checkbox below). Whenever this is enabled (even when it is not active), I have issues with MALTAB 2019A. When it is disabled, all works fine. Unfortunate, as I do use these accesibility features...

Viktor Mattsson
Viktor Mattsson on 2 Oct 2018
Edited: Viktor Mattsson on 2 Oct 2018
I have the exact same problem on my internal monitor, haven't tried with an external monitor. But the editor is very slow in Matlab R2018b, the cursor takes a couple of seconds to show up when I click somewhere in the code. Also when I want to run scripts I have to hover above the 1-2 seconds before I can click otherwise nothing happens when I click it.
Had the same problems both in macOS 10.13 and 10.14.
  1 Comment
Pontus Vikstål
Pontus Vikstål on 2 Oct 2018
Edited: Pontus Vikstål on 2 Oct 2018
I just tried with an external monitor. And I experience less delay, but still some delay which to me is unacceptable.

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Matthew Radice
Matthew Radice on 25 Oct 2018
Ok I disabled Matlab in the magnet drop down menu. Then I did a restart and everything is working as normal.
The magnet app remembers what apps you forget.
I hope that helps some of you as it really made Matlab unusable.

Thomas Gederberg
Thomas Gederberg on 19 Nov 2018
I am having the same problems with Matlab 2018b (also Matlab 2017a) running VERY slowly on Mojave. Unusable. However, I do not have Magnet installed (never heard of it), so that does not seem to be my problem.

Pontus Vikstål
Pontus Vikstål on 2 Oct 2018
I have exactly the same problem on my MacBook. When I click on a line in a script it takes about a second cursor to appear, it's super annoying.

Daniel Kovari
Daniel Kovari on 10 Dec 2018
BetterTouchTool ( also appears to cause MATLAB 2018b to have issues. In particular, using Java UI elements such as those included with the Widgets Toolbox causes MATLAB to hang (spinning beachball).

Sangjae on 27 Feb 2019
Edited: Sangjae on 27 Feb 2019
I have already raised this issue by volunteering with a beta tester for 2019a, but have received an answer that it has already been resolved.
BUT I understand that this is a situation in which the issue is being resolved. I would like to be sure that it is a problem with the Magnet app or Matlab's problem and should be fixed. I appreciate that I can use the MATLAB program, but apart from that, I do not understand that the company is staying as a temporary countermeasure for months without any measures.
  1 Comment
Anders Vestergaard
Anders Vestergaard on 25 Mar 2019
Edited: Anders Vestergaard on 25 Mar 2019
I have 2019a and it only works when i disable magnet...
Using MacBook Pro (15-inch 2016) macOS Mojave 16 GB ram

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Victor Murray
Victor Murray on 4 Apr 2019
I had the same problem with Matlab 2018b and Mojave 10.14.4.
Since I didn't had any of the Apps mentioned here to kill, I installed Matlab 2019a.... and had the same problem.
I was able to fixed by doing 2 things:
So far it is working.

tetonedge on 2 Oct 2018
I am having the same problem on a MacPro 10.13

Andras Joo
Andras Joo on 2 Oct 2018
I can confirm the same issue on MacOS Mojave/Matlab 2018b.
Does this has to do with OpenGL being deprecated on Mojave?

Matthew Radice
Matthew Radice on 19 Oct 2018
I am also experiencing these issues on Mojave.

Pieter Delobelle
Pieter Delobelle on 25 Oct 2018
Same problem on macOS Mojave, I also have the Magnet app installed. Hope this gets fixed very soon, matlab 2018b is basically unusable.

Giammarco Valenti
Giammarco Valenti on 2 Jan 2019
I experienced the same problem with matlab 2018b and Mojave. Quitting Magnet the problem was solved. The problem was only about the graphic interface of Matlab, because if I use and external editor and I run the scripts by the command window it works as always.

Anna Smith
Anna Smith on 14 Jan 2019
Yes, also running 2018b on Mac OS 10.13.4 with the same issue. After quitting magnet everything in the editor runs smoothly now!

Samuel Moczygemba
Samuel Moczygemba on 19 Feb 2019
My editor was extremely sluggish. For example, clicking "Run Selection" would take a few seconds for just the button animation to finish.
Magnet is a window manager for Mac. I do not use Magnet but do use another window manager named Moom.
Disabling Moom seems to have fixed the problem for me on a MacBook Pro running macOS Mojave 10.14.

Mohammad Azarnoush
Mohammad Azarnoush on 3 Apr 2019
Edited: Mohammad Azarnoush on 3 Apr 2019
I have the same problem. For about two months, everything was perfect. However, things started to get worse. When I open a script file, the cursor freezes; it is very vexxing. I don't have the magnet app or any other similar window manager. This is a really serious issue. Glad that I can work with python with no such errors.

Silvia Butti
Silvia Butti on 18 Apr 2019
I am having the same issue here. I updated from 2016b to 2019a and the delay makes Matlab unusable (about 30 seconds delay to open an empty figure, and several minutes to save and load files). The problem persists on both external and internal monitor. I do not have Magnet or any similar window managing apps installed, and I cannot disable source control as I am working with Git. I am running MacOS10.12 (so this is not an issue specific to Mojave). I still have Matlab2016b installed which works fine.
Any help or ideas on what to do would be greatly appreciated, thanks!

Marc on 24 Apr 2019
Exactly the same issue with new 2019a version on a late 2009 iMac 8GB RAM running onOS High Sierra 10.13.6, system slows to a crawl then crashes when plotting figures and using datasets of approx 1GB or more. Tried increasing the applied MATLAB memory capacity in preferences but to no avail. I am beginning to think it was a pointless purchase!!!

Richard on 29 Apr 2019
Edited: Richard on 3 May 2019
I am running Mac OS 10.13 (High Sierra) with R2019a & have the same problem (iMac with 8GB RAM).
I re-launched MATLAB & this time, I denied it access to the internet. And now it's ok.
Update, 3rd May: the problem has come back!! Fyi I do not use Magnet. Also fyi I never had this problem with R2017a which I have been using up to a few weeks ago.
Emily C
Emily C on 1 May 2019
I am also interested in this as the other suggestions didn't fix the porblem for me. I tried running it with the internet turned off on my laptop which worked (but not ideal). So hunted around a little more and went into service preferences menu item for the Matlab program and unticked the internet box as shown in picture below. I'm on Mac OS 10.13.6
This seems to make the program run normal speed now.
Richard on 2 May 2019
When I launch MATLAB it always asks me via a popup bix whether I will accept incoming internet connections. I usually accept, but this time I denied. And that fixed the problem. I never use the internet with MATLAB so for me that's not an issue. Hope that clarifies.

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Huxi Wang
Huxi Wang on 11 Sep 2019
I have figured out this problem!
macOS 10.14, matlab 2019a.
No matter it is Magnet app or popclip app, they are all related to srceen capture (text, image, etc.). These capture functions will interfere with matlab 2018b or matlab 2019a. So, what you have to do is just disable these functions, and everything will work fine.

Yixiao Wang
Yixiao Wang on 13 Dec 2019
Same issue for a long time...

Ran Xiao
Ran Xiao on 9 Feb 2020
Appreciate the inputs!
This has been driven me crazy and diabling Magnet works like a charm for me.
Just a add, you can choose to disable Magnet just for Matlab and keep using it for other apps.


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