Factorio Forums

Steps to reproduce:
1. Load the attached save file.
2. Make sure "show decoratives" is on.
3. Make sure you are underground.

What happens:
Small colored rectangles appear on the screen briefly at random positions. They continue flashing/blinking when the game is paused, and zooming out let's you see more of them (upto around 15 at once when fully zoomed out). They are also visible when in remote view, but not in map view.

Does it always happen:
I can always see them in this save, underground only. I have not seen them in other saves yet, though I usually play with decoratives off now. (Deleting all the decoratives from the console: /c game.player.surface.destroy_decoratives({}) also stops the rectangles from appearing.)

What I expected:
No random flashing rectangles.
Theories:
Since it looked like a memory corruption to me, I tried running memory tests, but they haven't found anything so far. I also tried updating my drivers, but this didn't seem to change anything.

Background info:
I use this save for testing mods, the last ones I tested were Subsurface and LinkedBelts, but I think the flashing only appeared after removing the mods from the save.

Laptop info:
Model: Lenovo T490
CPU: Intel(R) Core(TM) i5-8265U
GPU (integrated): Intel(R) UHD Graphics 620
Motherboard: LENOVO 20N3S3DN00
RAM: 8GB 2400 MHz

Oops I also posted this one incorrectly, I meant to post this as a bug report. Can it be moved?

Edit: Seems like Technical Help was the right forum all along.
Unless there's some memory leak in Factorio that's causing this, in which case the flashing rectangles wouldn't appear outside the game if I haven't played it since restarting my laptop.

To follow up on this, I still get the flashing rectangles with that particular save if "show decoratives" is on, but I also (very rarely) see a flashing rectangle appear outside Factorio, even when just doing normal stuff with my laptop, so I think there's an issue with my graphics card, possibly caused by letting it heat up too much (I used a fan control program, but I disabled it now).

It's a lot harder to catch them outside of Factorio, since I don't have a way to reproduce them, and it's only been a single rectangle for <1 second each time.

Take your laptop apart and repaste CPU and GPU. If you don't and it is indeed a overheating VRAM problem, then laptop may fail for good.

I do want to repaste (or thermal pad?) my CPU+GPU a bit further into the summer break. I disabled the fan control program I was previously using to delay the onset of the fans spinning up (probably dumb of me to use that, but I thought I kept it within safe limits), so I don't think it's of Immediate concern. I'm not faniliar with thermal paste though (and don't know what kind my laptop is using), so correct me if repasting is more important.


I tested the given save on my brother's computer with Factorio 2.0.76 (loaded from pendrive), and didn't get the flashing rectangles immediately when decoratives were on (same setup with my laptop does give flashing rectangles).
Computer info:
CPU: AMD Ryzen 5 5600G
GPU: Radeon RX 6600
Motherboard: MSI B550M PRO
RAM: 8GB 3200 MHz (x2)


Edit: Also tested in Factorio 2.1.7 on my laptop, and still get flashing rectangles with decoratives on in that save (I thought SDL 3 might change things).

Yodo wrote: Wed Jun 24, 2026 12:16 pm I do want to repaste (or thermal pad?) my CPU+GPU a bit further into the summer break. I disabled the fan control program I was previously using to delay the onset of the fans spinning up (probably dumb of me to use that, but I thought I kept it within safe limits), so I don't think it's of Immediate concern. I'm not faniliar with thermal paste though (and don't know what kind my laptop is using), so correct me if repasting is more important.


I tested the given save on my brother's computer with Factorio 2.0.76 (loaded from pendrive), and didn't get the flashing rectangles immediately when decoratives were on (same setup with my laptop does give flashing rectangles).
Computer info:
CPU: AMD Ryzen 5 5600G
GPU: Radeon RX 6600
Motherboard: MSI B550M PRO
RAM: 8GB 3200 MHz (x2)


Edit: Also tested in Factorio 2.1.7 on my laptop, and still get flashing rectangles with decoratives on in that save (I thought SDL 3 might change things).

You may have damaged your hardware by delaying the fans from spinning up, allowing the system to overheat under heavy load. Since you've disabled that program and the flashing rectangles are still present, it suggests that the RAM or VRAM may have suffered permanent damage.

I recommend repasting the CPU/GPU as soon as possible, as the problem could worsen over time. If you're not familiar with doing this yourself, it's best to have someone experienced handle it. Keep in mind that repasting is not guaranteed to fix the issue if the hardware has already been damaged.

To clarify, this is not a Factorio bug. The symptoms point to a hardware fault.