Shotcut is running very slowly (with Grammarly)


So I was here few months ago with Shotcut suddenly being slow. I figured that eventually (something to do with broken registry and I have no idea how I did it but I did fix it)

Now I have moved to Windows 11 and found that Shotcut is running slow. Again. I literally could not edit anything. I couldn’t even navigate menu without delays.

PC spec is fine. 3700x, shouldn’t have problem editing 5min video at 1080p.
I recently swapped out all but my old gpu.
Win11 is fresh install.
I even re-installed various versions of Shotcut

So what causes shotcut to be so slow that I can’t even navigate menu without even opening a project??

Turns out I had Grammarly add-on. Even though this was turned off while using Shotcut. So exit this one, then suddenly everything is fast again!

My question is: why?

Both my CPU & GPU didn’t struggle at all. CPU load was barely 10%.
and Grammarly isn’t exactly heavy.

btw, I’m not sure if this happens with anything else but seems like Shotcut is fine for now. just weird such conflict exists.


Can you clarify this? Do you have a Grammarly plugin for your browser? Or have you installed “Grammarly for Windows”?

I have not used Grammarly. I wonder if it hooks into applications to intercept the text in order to analyze it.


I did use grammarly, it doesn’t work stable for any app on my pc. So I uninstalled it.

I don’t usually install a spell checker, because the originals on its apps are fine and stable. Otherwise 3rd party apps don’t know what app you are using, and don’t make it stable to that.

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It was Grammarly for windows. I didn’t test with chrome extensions since i didn’t install one

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Thanks for clarifying. I do not know why Grammarly would make Shotcut slow, but it is a very good thing to know. This may affect other users.

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@Whispers - Oh my goodness, it’s just happened to me - so I was working on a project on my laptop. All fine - then I transferred to my Desktop (having copied all project files across to the equivalent locations on my desktop). Shotcut ran VERY slowly … delays with almost every click of the mouse or navigation. Unusable.
Then I remembered your post, and stopped Grammarly via Task manager.
Shotcut began working at full speed again.
@whispers - thank you so much for your post - it’s saved me potentially hours of head-scratching. I owe you a beer… :grinning_face_with_smiling_eyes:

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I had the same problem. As soon as I turned off Grammarly it started working. Thanks mate!

Same problem here, with my wife running Shotcut on Windows 11, suddenly on a rainy Friday afternoon complaining about performance issues and not being able to work with Shotcut, without any (automatic Windows 11 updates aside) software/hardware changes since the last time she was working with Shotcut without issues.

It was thanks to this post in another thread that I was lead down the path to Grammarly:

It took me several hours to figure this thing out, and I am a software developer (working on Ubuntu btw ;)). I asked my wife if she installed this Grammarly cr*p herself, but she could not recall. Maybe this malware was shipped with some automatic Windows update. One can only guess how many Windows users stumble upon this same issue not knowing how to fix it. We tried everything, from optimizing settings in Shotcut, CPU/RAM profiling, to rolling back Windows updates and Shotcut versions (including registry settings) to no avail.

Maybe it is worth mentioning this issue with Shotcut + Grammarly + Windows 11 in some troubleshooting guide, on the website perhaps? I could not find one.

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Another user reported that they had the same problem with Reverso Context and after they removed it, Shotcut’s performance was restored.

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