My browser / operating system: Windows NT 10.0, Chrome 133.0.0.0, No Flash versions detected
Scratch says browser don't support WebGL, while other sites says browser supports WebGL. Did anyone got the same?

I mean not. It fixed itself. I don't know why this happened, but few minutes ago I recently got two GPU crashes. So, this might be one of the the cause. Other could be glitch in Scratch or WebGL failing.

I had this same problem but it fixed itself too, I think its something to do with scrips that do a lot. bc it happens for me when a long animation played, but only happened if I was using scratch on a slower machine

Oh!

luna_the_good_cat wrote:

I had this same problem but it fixed itself too, I think its something to do with scrips that do a lot. bc it happens for me when a long animation played, but only happened if I was using scratch on a slower machine

There was someone encountered the same thing!

For real, Scratch is so glitched. The search function doesn't work half the time, the servers randomly crash, you can't look at griffpatch's followers… The ST needs to fix these

-UntoastedToast- wrote:

For real, Scratch is so glitched. The search function doesn't work half the time, the servers randomly crash, you can't look at griffpatch's followers… The ST needs to fix these

Of course we can't watch griffpatch's followers! Because, how much followers they have?

scar_x34 wrote:

My browser / operating system: Windows NT 10.0, Chrome 133.0.0.0, No Flash versions detected
Scratch says browser don't support WebGL, while other sites says browser supports WebGL. Did anyone got the same?

Are you using edge?

-UntoastedToast- wrote:

For real, Scratch is so glitched. The search function doesn't work half the time, the servers randomly crash, you can't look at griffpatch's followers… The ST needs to fix these

Scratch servers can't handle the load when you try to display all of griffpatch's followers, it's not “glitched” like you said.

-UntoastedToast- wrote:

For real, Scratch is so glitched. The search function doesn't work half the time, the servers randomly crash, you can't look at griffpatch's followers… The ST needs to fix these

You are 50% right. WebGL crashes after you load a large project anywhere that uses webgl. But scratch crashes for griffpatches followers.

I'm going to tell you about very common bug!

If you want to tell you how to fix it, scroll to the final!

1) What the “GPU bug” really refers to
A. GPU‑related performance errors shown in the browser

Some Scratch users have seen browser console errors like:

GL Driver Message (OpenGL, Performance, GL_CLOSE_PATH_NV, High): GPU stall due to ReadPixels


This message was logged repeatedly when running certain Scratch projects and corresponds to WebGL/GPU pipeline stalls — not a Scratch internal error message, but a GPU/WebGL performance warning emitted by the browser/driver.

Key details:

It happened only with specific Scratch projects, not universally across all projects.

The message points to a function like readPixels(), which is known outside Scratch as a blocking, pipeline‑stalling WebGL call that can kill frame rates because it forces the GPU to synchronously return data to the CPU.

Users speculated that inefficient use of code or large textures could trigger GPU stalls in Scratch’s WebGL renderer.

Discussion angle: this isn’t a Scratch Engine crash bug per se — it’s a GPU pipeline/backpressure/driver warning that impacts performance. Scratch itself doesn’t expose low‑level GPU APIs, so the bug manifests through WebGL.

2) Why this relates to Scratch’s rendering (WebGL)

Scratch runs in a browser and uses WebGL for rendering the stage:

Scratch’s 3.0 engine uses WebGL (the browser’s 3D graphics API) to draw sprites, backdrops, and effects on the stage.

WebGL communicates with the GPU via the browser’s graphics driver. If the browser encounters operations that force read‑backs or synchronization (like readPixels()), it can trigger GPU stalls.

Technical insight:
WebGL is not primarily designed for high‑performance compute — it’s designed for graphically rendering frames. Operations that interrupt the render pipeline or try to retrieve large amounts of data (like reading pixels back to JavaScript) can bog down the GPU and cause lag or warnings.

⚠️ 3) Common symptoms reported by users

Here are typical GPU/visual issues in Scratch discussed by users — these aren’t all necessarily the same bug, but they relate to GPU/WebGL behavior:

GPU stall errors

Projects displaying repeated “GPU stall due to ReadPixels” errors in the browser console.

Extreme lag or low frame rate in some Scratch projects that don’t normally lag — possibly tied to textures or effects.

WebGL availability issues

Scratch sometimes showing the “Your browser does not support WebGL” error even on systems where WebGL should work.

This can be tied to the browser blacklisting GPU drivers or disabling hardware acceleration.

Frame rate drops

Reports of Scratch/TurboWarp running significantly below expected FPS in certain browsers, even on capable GPUs.

Rendering anomalies

Large vector costumes or huge images sometimes not rendered correctly because WebGL texture size limits are exceeded — this is a GPU/WebGL constraint, not a Scratch engine bug.

Potential underlying technical causes
✅ 1. WebGL driver and GPU pipeline behavior

WebGL doesn’t expose every GPU control, and calls that force GPU → CPU synchronization (like reading back frame buffers) inherently stall graphics pipelines. Scratch’s rendering might trigger this in certain conditions — even if Scratch code isn’t explicitly calling such functions.

✅ 2. Browser hardware acceleration settings

If a browser’s hardware acceleration is disabled or if the graphics driver is blacklisted, WebGL performance degrades or fails — Scratch might refuse to run or fall back to software. This can look like a “bug” to users.

✅ 3. Browser/GPU driver compatibility

Browsers sometimes block WebGL features on certain GPU drivers because of stability issues — meaning Scratch won’t use the GPU properly even if it’s present.

Why this isn’t a simple Scratch internal bug

Scratch is primarily a web application running in a browser; it relies on the browser’s graphics stack (WebGL, OpenGL/ANGLE, drivers). So:

GPU stall warnings aren’t necessarily caused by a Scratch bug — they are side effects of how WebGL is being used.

Many GPU issues can come from the browser or drivers, not the Scratch engine itself.

This means when we talk about a “Scratch GPU bug,” we’re really talking about:

how Scratch’s use of WebGL interacts with browser GPU drivers, and how certain operations expose performance problems or limitations.

Points to highlight in a discussion

1. WebGL isn’t perfect and has limitations — synchronous operations like readbacks can cause GPU stalls even in well‑written code.

2. Scratch doesn’t give direct GPU access — so the bug symptoms are usually indirect and work through WebGL.

3. Browser/driver environments matter — hardware acceleration settings, driver compatibility, and browser blacklists affect whether Scratch uses the GPU at all.

4. Community reports vary — some users report lag, others see errors, and some hit WebGL unsupported messages — meaning the “bug” is broad and contextual.

Conclusion

The so‑called “Scratch GPU bug” isn’t a single defined software defect in Scratch. Instead, it refers to a set of GPU/WebGL‑related issues that appear under specific conditions in the browser environment. These can include performance stalls due to WebGL operations, hardware acceleration challenges, driver compatibility problems, and texture/rendering limitations.

If you’re turning this into a discussion topic, a good structure might be:

What WebGL is and how Scratch uses it

Typical symptoms reported

Browser/driver vs. Scratch engine responsibility

Why these issues are tricky to fix

What users can do (e.g., toggle hardware acceleration, try different browsers)


I have this problem, it is soooooo glitchy, I can't play any game! I can't run ANNYTHING! It is EXTREMELLY GLITCHY!!!

The problem is in Chrome, if it happens to you, open > chrome/gpu <
There you'll find why!

scar_x34 wrote:

I mean not. It fixed itself. I don't know why this happened, but few minutes ago I recently got two GPU crashes. So, this might be one of the the cause. Other could be glitch in Scratch or WebGL failing.

if your WebGL crashes, do not reopen the browser, it may risk.

have you tried these?:
1. hard refresh Ctrl Shift R/Cmd Option/Shift R
2. go to a different browser and export your adds and extensions
3. clear cookies safely

this is lifesaving!! thanks!