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Crash on startup (Error 134 / Missing SSE4.2) #59461
Description
Description
Hello,the recent update of the desktop client has introduced a breaking change for users with older processors. Due to the new Bun runtime requiring SSE4.2 instructions, the application now immediately crashes on startup with error code 134 ("this CPU is missing SSE4.2 support").
At the same time, previous versions of the client are now restricted from accessing free models, creating a loop where it is impossible to use the software on older hardware.
I was in the middle of a project development where the app was managing files inside my local engine, and now my entire workflow is interrupted. I understand that I might be among the few still using older hardware, but this project is deeply important to me, and my current setup is the only way I can practically work on it.Could you please consider providing a legacy branch without mandatory update checks, or restore compatibility for CPUs without SSE4.2?
Plugins
No response
OpenCode version
No response
Steps to reproduce
- Launch the latest version of OpenCode Desktop on a Windows PC with an older CPU (lacking SSE4.2 support).
- Observe the application immediately crashing on startup.
- Read the console output showing error code 134: this CPU is missing SSE4.2 support, which Bun requires.
Screenshot
Operating System
Windows 10 pro
Terminal
Windows 10 × 64
Activity
opencode-agent commentedon Oct 27, 2026
Thanks for the detailed report, and sorry this broke your workflow in the middle of a project.
To restate the request: you'd like OpenCode Desktop to run on CPUs without SSE4.2 support, or a legacy build without forced updates that can still use the free models.
Some background: the crash comes from the Bun runtime itself, not from OpenCode. The Windows desktop app already bundles the most compatible "baseline" build of OpenCode, but even Bun's baseline build needs SSE4.2/POPCNT (x86-64-v2, roughly Intel Nehalem / AMD Bulldozer and newer). An earlier change (#47297) already lowered OpenCode's requirement from AVX2 to that baseline. Going below it isn't a simple bug fix; it would need a different runtime or a separate build. I've marked this as a feature request so maintainers can consider it, but I can't promise anything.
Related issues:
If you can, please reply with your CPU model and the last OpenCode version that worked for you (if you remember it). That will help maintainers understand the scope.
Evgeniy57Ronnsen commentedon Oct 27, 2026
Thank you for your support.
My PC specs are:
• CPU: AMD Athlon II X2 255
• RAM: 3 GB
• OS: Windows 10 x64
To clarify the version: everything worked perfectly fine on either version 1.18 or 1.19 (I don't remember the exact build number, but it was one of these two).The issue is that the application now forces me to update to version 2.1. When I install version 2.1, it immediately crashes with error 134 on startup. But if I stay on the 1.18/1.19 version, it completely blocks the chat.Furthermore, before the update screen appeared, I was hit with automatic 24-hour bans for 3 days straight without any reason. I would get unbanned, type a single word like "hello", and get banned for another 24 hours immediately. At the same time, all the text stats in the right-side context panel(Model, Total Tokens, Input Tokens, Reasoning Tokens) turned into blank dashes, even though everything was working perfectly before.
If it is possible to disable this mandatory update screen for the older 1.x branch, or provide a legacy build for version 2.1, it would save my ongoing project.
Thank you again for your time.
nzxweb commentedon Oct 27, 2026
i have the same issue.
my pc specs are:
Core 2 Duo T650 2.0GHZ
Ram: 4GB
OS: Windows 10 x64
DashSlash01 commentedon Oct 29, 2026
I'm experiencing the same issue.
System Information
Operating System: KDE neon User Edition (kernel 7.2.12-1-liquorix-amd64)
CPU: Intel Core 2 Quad Q9550 @ 2.83 GHz
RAM: 8 GB DDR2
GPU: AMD Radeon RX 550 Series
Last working version of OpenCode: 1.19.5
Issue
OpenCode Desktop versions in the 1.x series display the following message:
This version of OpenCode Desktop no longer supports free models. Update to the latest version at https://opencode.ai/download to keep using them.
On the other hand, versions in the 2.x series crash with the following error:
SIGILL (Illegal instruction) on x86-64-v1 CPUs (SSE4.2/POPCNT missing).
It seems that newer versions are incompatible with my hardware. Is there any workaround?
Thanks.
wahidmounir commentedon Oct 29, 2026
the issue with opencode v2 is that it is built using bun which does not support old CPUs. so I built it using Node.js instead, but when I tried to use it, immediately it says that I’ve reached the usage limit—even though I haven’t started using it.
Could you provide a Bun-free compiled binaries version that runs on Node.js? Node.js 26 still supports older processors, so this would let users with CPUs that lack SSE4 run OpenCode.
fsalim1983 commentedon Oct 31, 2026
Hi, I am also facing the same issue with OpenCode v2 crashing on startup due to missing SSE4.2 instructions.
Hoping for a Node.js fallback or compatibility build in the future. Thanks!
Evgeniy57Ronnsen commentedon Nov 9, 2026
Hi ,It’s been two weeks since this issue was opened, and the lack of an official response is concerning. My ongoing project has been completely halted for 2 weeks because of this update.
I relied on your software to manage actual work, development, and my project. While I understand the decision to evolve the product and move forward to a new technological stage, every user has different technical setups and hardware. This never stopped me from successfully working on my project until recently. It is completely understandable that you want to progress, but at least some alternative should have been provided for the rest of the audience. Right now, you are completely cutting off a segment of your audience, leaving no choice and no chance to continue working.
Due to the switch to the Bun runtime and its mandatory SSE4.2 instruction requirement, the v2 client crashes immediately on my CPU. Third-party Node.js rebuilds or unofficial workarounds simply do not work. Furthermore, completely blocking the older, stable versions (1.18 and 1.19) on the server side has stripped me of any fallback options.
Lately, even before this update, the system was already locking me out for 24 hours or several days for no clear reason, sometimes just over a single word, even though all tokens were completely available. And now, you have taken away my working tool entirely.
Please provide a straightforward answer and bring some clarity to this situation: does the development team plan to take any action to address this issue, or has support for this hardware tier been officially dropped? You are providing absolutely no updates or explanations, and I need to clearly understand what to expect moving forward. I hope for a constructive response. Thank you.