+27 votes
in Bug Report by
edited by
I've had this issue in my game for a long time, and I don't really see anyone else experiencing this, which leads me to think it's an optimization issue that my crappy computer is struggling with.

So what happens is I have items going into a splitter, the splitter will stop outputting despite having a belt with space going out of it. It has to have at least 2 outputs, and one output has to be backed up. If I remove an item from the backed up belt, everything starts running as designed again.

My theory is that the splitter has allocated an item to go out of a specific port, but then there isn't space for it to output, so it backs up the line and the other outputs starve until that item can leave the internal buffer.

Please help get this noticed because it essentially makes manifold builds impossible on my game.

Edit: This is with a regular splitter, not a smart or programmable one. I am currently on the stable version, but have been having this issue since before the last major update. It does seem like since the previous experimental version went to stable, that when I am nearby the issue is reduced, but they still get stuck. I can provide video evidence if anything is unclear.
edited by
If you're talking about a smart or programmable splitter then this is behaving as designed.

"Please use the search function before posting a new question and upvote existing ones to bring more attention to them, It will help us a lot. <3"
edited by
No, if I were talking about smart splitters, I would have said smart splitter. I am talking about the regular splitter.
Other than my own older posts requesting help with this issue, I've only seen one other post that appears to be similar, and his fix did not fix my issue.
Have you tried demolishing and then  rebuilding?
This seems to have worked for others with splitter problems - especially after upgrading the belts.
by (210 points)
I have on some parts and it didn't seem to make a difference. The biggest issue is that it seems to happen on so many splitters... I'd basically have to gut every factory and start over. And many of these were built with mk4 belts, so I've never upgraded the belts with them.
I was toying with the idea that the ones snapped to belts are the ones with issues, but my fuel generator line struggles as well, and those splitters were placed on the ground.
by (210 points)
Not really the same issue. Mine all have mk4 belts on them, so 1 mk4 in and 2/3 mk4 out. I believe all of them were built with mk4 belts, so I've never upgraded the belts on them.

I would also like to point out it states that splitters will try to send them out the front, then the sides. Mine has a front open, and 1 side backed up, but it is not passing items through.
by (130 points)
I observed this behavior on several of my splitters as well. It seems to get worse the faster the connected belts are / the more items they carry. In one case, I watched a manifold feeding 12 assemblers each with 60 quickwire a minute using a mk5 belt @ 720 / min - one of the first three or so splitters would get stuck and not let any quickwire go further down the line until the connected assembler is done producing and taking in the next items. It occurred several times over just one minute and since its kind of self resolving, I assume it happens all the time throughout my factory, presumably crippling its efficiency.
by (210 points)
This is exactly what I experience in my factory. I'm glad to see I'm not alone with this problem. It didn't occur to be that the belt speed could be a factor, but now that you say that, all the places I notice frequently have problems are all my bigger factories with mk 4 belts. My older factories with slower belts I've never seen do this. Admittedly I also spend far less time watching them.
by (450 points)
I'm having splitters clog up and just stop working after they have been working fine.  Please see this https://www.reddit.com/r/SatisfactoryGame/comments/cad8hg/weird_splitter_bug/
by (260 points)
I've had this a couple of times too
by (190 points)
Having the same issue in multiple locations of my nuclear fuel facility, hope this is fixed soon.
by (290 points)
Same problem , i think the mk5 belt is bugy whit separator, the separator act as a buffer
no problems whit mk4 belt

by (450 points)
I think it may be belt type specific issue as well.  It's just the mk5 belts with the issue?
by (260 points)
Others including me are reporting the issue with MK4..
by (290 points)
Strange , i have only whit mk5 belt , no mk4.
by (660 points)
I got the same issue even with MK4 in all output of the splitter.
by (110 points)
Having the same issue, with both MK4 and MK5 belts. Some have MK1 belts going to the machines with MK4/5 belts in and out as the "main line"
by (290 points)
edited by
I divide the mk5 belt on the mk4 before the machines, it solves part of the problem but the flow is not constant on belts mk4 and there are production losses
this problem does not affect groupers only it affects separators,.
I have tested with my machines off, without any lag, it is not cause by a performance load of the game.
Some players said they do not have this problem, it may be a map or chunk corruption I think.
by (32.9k points)
This bug is kinda troublesome indeed
by (160 points)
Hello all.

New to this game and have run in to this problem.

I only have a very small factory set up so far.

I am trying to splitt a conveyer from my iron mining station in to two melters but it is not working.

I have put a conveyor splitt on the conveyor from the mining station and run new conveyors from left and right side on the conveyor to two melters, but nothing comes out of the splitter and the conveyor from the mining station full of ore has stopped.

The conveyor belts and the spiltter are the types that you first unlock.

The way i cinstructed this was first to install the miner, then conected conveyor belt to it, from there installed the splitter and finally the conveyors frotm the sides of the spliter to the melters.
And if someone is wondering, the arrows are the correct way.

What are I not getting here? Anyone can help.

I have also a picture of the set up at imgur, if you want to see it: https://imgur.com/a/UukUdnX


I have tried a combintaion using the middle output also. I'm using a gaming laptop, I7, 16Gb with GTX 1060 6Gb, so I think (hopes) the FPS is not my problem. Have tried to lowering graphcis setting without luck.

by (260 points)
I'm running on a much lower spec laptop than you so FPS are not your issue. The issue you have posted isn't the same as others in this post, as you would have one full belt on the output..

You don't look advanced enough to have smart splitters etc... As could be that you haven't set the output..

So the most likely explanation is that the input belt is not connected to the splitter properly.. and is connected to a conveyor pole perhaps... Delete the splitter and belts and conveyor pole if there is one, then try again.. it shouldn't matter in which order they are connected just out down the splitter then connect your belts, the 3 lines signify the input and the arrows the output (if you look on top)
by (450 points)
This is an issue that has since been resolved by game updates.  Check post age before responding.

4 Answers

+4 votes
by (15.9k points)
As a few of you suspect this is related to lower fps, we've identified the problem and are working on a fix, the problem is quiet complex so I can not say when the fix is going to be done.
by (1.1k points)
edited by
Hey Gustav, i have begun runnning my newest factories (380 assembler, 340 constructor, 200 manufacturers etc.) in my 290MB save file, which also causes the splitter bug in several locations.
What I can add is that not only splitters do get stuck but also the loading of train cargos sometimes do work and sometimes do not work. In my save this relates to the fully loaded and fully supplied freight station in the 'uranium tunnel' (middle of the map), which is sometimes unloaded by the automated train and sometimes not.
To be certain: yes, no changes to the route and time table at all and all stations are powered and set to load/ unload properly.
EDIT: Driving and loading/ unloading the particular train always works fine.
by (15.9k points)
Hi, a fix for the splitter issue is on the way, probably coming to experimental today.

As for the trains, I'll have to look into that, do you mind sharing your save with us? (I'll PM you where you can send it)
+1 vote
by (690 points)

Same Issue on Experimental CL#102556


0 votes
by (300 points)
I am experiencing the same issue.

I'm gonna state here how to reproduce this, but the exact conditions are unknown to me. I'm sure it happens after some time, but I never observed the behavior.

This is my setup:


The basic layout of a five-way splitter. After time spent not being close to these setups, they eventually came to a stop outputting to the empty conveyor belt.

I expect this behavior to have the following origin:

Since the cycle between the four mk4 belts is saturated, and the merger tries to feed more items into the cycle, it eventually comes to the conclusion that the cycle is only a performance load and the splitters stop distributing. I am sure that it is due to some optimization. I have not tested, if the setup is fixed by replacing the belt with 120% load by an mk5 belt, but I expect that to be the case
0 votes
by (210 points)
I have an update for this, that is a solution, but not one that is very practical. I've since upgraded my computer. I went from a surface pro 4 to an actual gaming PC and my issue with splitters seems to be resolved. (Also my lag issues, but they are probably related.) So it does indeed seem like it is an optimization issue that it causing this.
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