Linux, Bazzite 43. Shotcut installed via flatpak on Bazaar.
What is your Shotcut version (see Help > About Shotcut)?
25.12.31
Can you repeat the problem? If so, what are the steps?
Make a ~3 hour recording using H.264 and 2-channel 48kHz AAC at 384kbps with multiple audio streams (I use 2).
Open 4 instances of Shotcut and create a new project in each one. For the project to be used in testing, create a video track and an audio track.
Import into Shotcut playlist and from there into the timeline, in the video track. While the audio waveform is generating, add the same track to the timeline’s audio track, go to Properties, and switch to the second audio track.
While the waveforms are generating, if you can still do anything, jump to about halfway through the video stream and make a cut.
I keep an eye on my RAM while I’m doing this, and in the previous version (25.10.31), Shotcut held steady at about 6GB of RAM. Now in 25.12.31, it varies from about 8GB up to 20GB, at which point it generally crashes. If I take it really slow, I can sometimes work my way through the project, but oftentimes just adding a cut makes RAM use jump by 300-500MB.
I have the same version of Shotcut installed on my Windows partition (same hardware as my Linux install), and it does not have this problem.
As a temporary workaround, does anyone know how (or if it’s possible) to downgrade my version of Shotcut in Bazaar?
I don’t know Bazaar, but you can download an appimage and work with it without uninstalling or replace your flatpak
Version 25.10.31 (like you had before) > Release v25.10 · mltframework/shotcut · GitHub
If you’re not familiar with appimage, once downloaded, right click on it, go to the tab permission > Allow executing as program (or similar on Fedora) > OK, then just double click on it, it opens you’re ready to work (no installation needed)
What is your Settings > Processing mode in the 25.12 version? You need to open the project if you saved one and look after you open it. The new 10-bit modes require more memory.
Thanks @Patrice for the workaround. I’ll try the AppImage solution–I was able to downgrade it via flatpak but the next time Bazaar checked for updates, it updated Shotcut. Doesn’t appear to be a way to tell it to not update certain apps.
@shotcut My processing mode is set to 8-bit. I do think there is some kind of bug in the 25.12.31 version. From the other discussion I started a few weeks ago regarding using .mkv files in Shotcut, the first time I remuxed a file and ran it through Shotcut, it worked great (this was on 12/29/2025). Then a couple days later, 25.12.31 released, and every long video file is causing Shotcut to triple its memory usage and eventually crash. When I downgraded to 25.10.31 and used the exact same files in the exact same way, I did not experience this issue.
I’m on Linux Mint-MATE, in the “update manager” I go to Edit > Preferences and I got this screen on the tab “automation”, as you can see my Flatpaks will NOT update unless I give a go
I’m sure on your distro you have something similar or even better , I mean you’re on a Fedora based distro, which is a well known distro for its cutting edge tools
The only thing I can do is to show you what I can do on mine (sorry), hopefully giving you some idea reproducible in some way on your distro (I never used Fedora)
Thanks, though Bazzite offers… woefully little control over this! It uses Bazaar, which as far as I can tell, cannot be told to not update… And what control Bazzite offers is VERY binary–either you allow system AND application updates, or you disallow them both at the same time. Kind of frustrating, tbh. I really wish Bazaar let you choose an application version and keep it, as well as determining on an app-by-app basis which ones you want to keep updated.
Reporting in. This issue is still affecting version 26.01.30. Shotcut just outright crashes when I try to add a long video to the timeline. It will start generating the waveform, get to about 2/3 of the way through, and then just crash to desktop. I am uploading the crash log to this post (sorry, I thought I had uploaded it previously). Hopefully that helps. The crash log is from version 25.12.31 but the crash is the exact same, and I am not installing the latest version right now to mess around with generating a crash log, since I need to edit my videos and have already spent too much of my time time dealing with this bug.
The main problem with this crash is how Shotcut’s timeline handles memory. When you add long videos, waveform generation uses up a lot of RAM, and in 25.12.31 and 26.01.30 it doesn’t free it up correctly, which makes the program crash. Flatpak builds make things worse on Linux because of sandbox limits. The easiest ways to get around this are to break long clips into smaller parts or use the native Linux build instead of Flatpak. The native Linux build handles memory a little better. To fully fix it, developers will need to fix how waveforms and memory are handled.
Yeah, this issue didn’t happen at all in 25.10.31. I’ve downloaded and extracted the tar with the native build, which is fine. I just wish there was also a way to tell my app manager “don’t update this app” / “use this specific version until I say otherwise”. Bazaar doesn’t let you do that, to my knowledge.
None of the main developers are able to reproduce the problems described. “Shotcut in Bazaar” means nothing to us except that I guess it is not one of the builds on our download page. “recording” is not clear. It could mean a camera of which there are many, game recording, screen recording. We do not have many 3 hour videos so often end up generating one with Shotcut.
Haven’t seen that here either. Maybe it will if you use a problematic file such as a MKV from OBS as discussed elsewhere here.
You seem smart; so please help the world and try to fix it.
If the symptoms I’m seeing are a result of using the flatpak version of Shotcut, what I can do is try the tar of the latest Shotcut and see how that handles these large files. If it can chew through them without crashing, I’ll just close this bug as that would clearly point to an issue with the Flatpak format itself, not an issue with Shotcut.
FWIW, the files I have been working with are screen recordings of games. Originally I was using MKVs but at your advice I switched to using hybrid MP4s, but the issue cropped up for both formats starting with the 25.12.31 version–I didn’t know Flatpak had some different rules and containerization compared to the official/tar version (I’m a Linux neophyte).
Anyway, I’ll give the latest tar a try this weekend, when I’ll have another 3-hour video to chop up, and I’ll either be back with some log files and shed tears or “nothing to see here” and close the bug.
, I mean you’re on a Fedora based distro, which is a well known distro for its cutting edge tools 
