Console devices lag out multiplayer users when saving files

Back when the Legendary Artic Phoenix was given out for free (2-3 years ago iirc) my kids had difficulty getting it to load at all on the Switch. I think it may be the high-resolution textures that trigger the problem.

Is your main test world where you reproduce this a purely vanilla world, or are you using any resource packs?

First of all: My main motivation for providing the bug report at all. Bold is just emphasis, as this is a long post, not yelling, btw 😃:

I feel recent {}software changes, likely made for real reasons, have likely significantly degraded the for-free multiplayer experience which Minecraft has had up until very very recently. It is incredibly unlikely this was intentional, but as there are servers you sell to run the game, and you have new paid Minecraft IPs (Minecraft Legends), etc, the point should be made that it's "not a good look" for people looking to cast that aspersion (which I am definitely not).

I personally don't think these are at all linked. I think the internet, generally speaking, has a pretty dodgy grasp of correlation vs causation. Summer vacation and it's attended travel just started in many parts of the US and lots of families are going to be experiencing this bug (as realms and wifi are going to be less certain, and more local play will occur).  I assume, if this bug is as widespread as I suspect it likely is, fixing this may become surprisingly high priority if that happens and wish to equip the team to do so if they choose to do so. ** 

As to why I pointed at the scenarios:

When we played Arctic Phoenix after getting it for free a couple years ago originally, it had basically no real problems loading for us on a 2017 switch (plugged in and shown on a TV) and 2 clients (2020 normal switch in handheld mode  and a 2020 switch lite also in handheld mode).  We are fairly religious about moving games to the system memory vs (the fairly high speed) SD card if there are performance issues, so that may have been the performance difference for us? 

Apologies if I was unclear about why I was mentioning the scenarios: I'm not specifically charging the core Minecraft team with responsibility to make sure all these scenarios work in all situations. I felt pointing out scenarios available on the Minecraft store which quickly demonstrated this bug when 1 switch host and 2 switch clients were being used (or even 1 and 1 often), would be an easier way to reproduce than just giving a Minecraft world which is not a predictable result to get to. 1 server 1 client seems basic "gotta have that working to advertise the game has local multiplayer" level of functionality.

I'm reporting failures in very typical vanilla worlds which have very reasonable sizes recently becoming unplayably bad in local multiplayer. I bring up these store scenarios as clear exemplars of things which stimulate essentially the same bug for us.  Kids playing in vanilla survival would easily get to this complexity of a world in a couple days of plays. 

We have experienced this on multiple vanilla worlds as well. The main test world is a vanilla world and we actually only checked the Legendary Phoenix and Minecraft: The Mountain to try to find an easy reproduction to show what would cause this bug as it really did feel like a general performance degradation of the core stack, and not a "world based problem".  

As in, I thought the test team could restart the Mountain scenario repeatedly to see what the threshold is for failure as it quickly gets to these sizes, but the vanilla world we most recently worked on, for instances, would take many hours of replay to get it to a threshold place which definitely causes the behavior and it might not if you don't do something specific with animals or the nether or a village etc. It only takes about 15-25 minutes of play for even a 7 year old, for instance, to get Minecraft: The Mountain far enough along to cause this issue. We saw the issue by the time we got to the "Collect these 6 items quest". I assume a professional tester would take about 7 minutes to repeatedly get to that point. 

I say this because the fault (saving becoming so overly prioritized it boots clients after causing lots of lag), is very likely (from a software perspective) not simply "exactly 50MB" and you'll definitely see it. Serialization of a Minecraft world to a file possibly takes longer based on specific complexity and specific happenings in world, and I knew both of these scenarios had a lot going on there and would be likely to demonstrate it.  It may not even be serialization, but the snapshotting or something like that. I just wanted a state easy to get to and to get to similar states repeatedly which do not exhibit the error as well. For instance, at the beginning of that scenario, for instance, all 3 people can play and the saves do not lag us out, take an undue amount of time, nor anything like that. The scenario itself (if you follow it's directions) also quickly tells you what to do to reproduce the bugs (as you just play with 3 switches enabled and you'll see it happen after not that long). 

In our recent vanilla world, there are a few animal pens, some growing crops, and a things like that near our home base. Nothing YouTube worthy, but nothing "this should clearly break the game". We probably haven't built a mine cart yet and the most red stone we have is 5 observers on a tiny automated sugar cane greenhouse which is tiny (like 5-6 stalks wide, one line) and textbook.  But the fact there are X sheep or Y cows could be the issue in that world, rather than the exact number, and we'd never know. (Note: being far away/in the nether while the animals and crops exist does nothing to help the bug).  We moved some work tables around in a village fairly far away, and discovered a Forest Mansion and built a long cobblestone path through the nether. We built a couple mines (not automated). We have a box which automatically composts stuff you put in a hopper, and a similar box which automatically cooks food you put in a different hopper. Essentially very basic, not very demanding (from what I understand) of a world.  

Many of our other former worlds have much more in the way of minecarts and things like that I feel would likely exacerbate the issue/make people go "it's clearly the whatever which is too much", but I'm willing to investigate if that would be helpful for some reason. We built this world "light on the machine" per se, from what we understood. 

If uploading our particular file of this particular vanilla world would be that helpful, I'm happy to do it; I just need to link my daughter's account, upload it to a realm, then download it on a desktop computer. Hell, I'm happy to connect up a debug mode client or something locally on a Mac or windows computer and export logs. I am a professional programer (mostly iPhone) and am willing to climb down the "enable all the log files" rabbit hole if it's of use next to a system reliably exhibiting the fault.

I'd honestly expected this bug report to be "oh, that's a better reproduction for [Known bug so and so] than the one we have" and just be hot linked to a dupe in the JIRA. I really don't expect this to be a unique bug at all: I think this is a performance regression, probably deeper than was intended, and the team is likely partially aware of the chance of this happening, just not how quickly it does. Just tried to bring value to show "Look, all this stuff that used to work now doesn't, things really are getting worse, and likely past the commercially acceptable point all things considered". 

For instance: Despite repeated 10x - 20x times we logged into the game from the switch lite above on 6/4/23, the Nintendo Error log only shows 2 error 2306-0332 that day (that's the black screen switch error you get when the network disconnects). Those two errors are when hard shutting down the Minecraft software (home button then X), not the game.  When in the past we've ever seen a game repeatedly have network issues, we've seen those happen far more in these kinds of error logs. 

I'm happy to provide account IDs and switch IDs the appropriate way and upload it if there are error reporting analytics to correlate to. If you have a document about "How you don't get pwned when helping us solve bugs and providing PII!" document to make sure I do that the "appropriately secret way", let me know.  Re bog standard JIRA, "Viewable by All Users" toggle will not let me select any group other than "users" when changing who can see comments. so I bet "just drop that info in a comment" is not the right way to provide that data with this particular site. Happy to become more well informed as well on "how Minecraft works" to try to repro better if needed.

One relevant point I'm not sure I said: The host for this game does not have a Microsoft account (yet). The secondary and tertiary Switches were played by players who do have one, but the errors occur whether or not those players were logged into the MS account or not. 

This issue seems pretty close to what I'm experiencing so I'll provide some additional details that I noticed.

I play on the switch with some friends and family. My world was made in 1.17 and my sister made hers in 1.19. We'd frequently play together without problems. Ever since the recent 1.20 update, when we join each other, we can only play for a couple of minutes before the non-host player loses connection. (Also when joining the world, the non-host player sometimes has a wiped inventory, as if they're joining for the first time.)

Single-player in our older worlds works just fine.

Tonight we made a brand new world and everything worked perfectly fine and we had no connection issues.

The bug might be size related, like OP said, but it could also be related to something in the new update breaking or lagging older worlds. (Not sure what that might include though especially since it's a multiplayer only issue.)

I've been having issues like this for a few days now, i often play online multiplayer and our group has finally settled on a world to put some hard graft into. we initially believed it to be down to the fact we were spread quite far across the map, i for instance being somewhere around x:1500, z:1500 and the home base being at ×:2, z:-400. the game was having a hard time loading chunks and my friends would die due to a mob they couldnt see or a fall and then unable to rejoin. it has however gotten worse in the past day or two regardless of map location, i (being the host) get a notification: named player has drowned for instance, while that player is in fact live and on dry land. in this case the other player has the decreasing air bubbles and has to watch themselves die only then to be unable to join without multiple game/console resets. there have been occasions where players are unable to interact with chests/beds/blocks before being kicked and its gotten to a point where at least one other player can anticipate a kick due to lag. there's never more than 4 of us max and this occurs even with just 2 of us, though it is less laggy with less players. its literally making the game unplayable when every hour we spend a good 20 minutes trying to get everyone back in the game, loading and reloading. 

we've also on multiple occasions now, myself included, lost inventory on respawn. not too much bother most times, but some valuable items have been lost that will take hours more gameplay to replicate. one player has turned to joining the game from their xbox as the switch would not log in nor accept invites but its just as bad there. 

+1, but on iOS , iPhones

Me (second player) and my sister (world host) have a minecraft world. I join through our accounts, not LAN, and I get disconnected constantly. No constant trigger or time between disconnections. Our phones both work completely fine and it is not a WiFi/internet issue. I tried deleting and reinstalling my app, successfully logged back in through xbox live and joined her again and it only made the disconnections more frequent. We have no external resource packs or mods applied.

Something about the lag I'm experienceing has changed from .60 to .62. Everytime I look in the direction of the host player on Xbox, massive lag happens. However, the same seems to happen when the host comes near me. It seems to be worse when the player doesn't move for a little while.

Edit: I forgot to mention the change itself: .60 things improved but .62 brought it back.

Is Minecraft installed and saving its data on your device's internal storage or an external micro SD card?

Internal storage

*strong text*Internal and SD card storage both show this issue. Multiple different switches as host show this issue. Using mesh wifi (eero) or direct wifi (google fiber, dlink, att) show this issue. Using resource packs or no shows this issue. Using no packs, simplest fast wifi and “not janky machines” eventually still shows this issue.

I only mentioned scenarios and such as it was fast to reproduce. There was not a workaround, very basic small farms or any standard exploration would eventually show the same issue.

You can repeatedly stimulate this issue with small farms (a few foods grown, then a pen for animals which you can walk around and toss lots of food), then send one of the other two players out of chunk, perhaps through a portal to another area. The whole goal is getting the sync effort high. The configuration of three players on local network sync on three switches with a ~50 mb save file alone will repro the error when done naturalistically. I do not know how big a “trivially” generated large save file (like overly exploring with a boat or something) would have to be to generate the error but basic minecraft “build a base” stuff fails after a couple of days of play with this limitation.

We have tried a few nintendo switch versions to see if the error is corrected. We can do so again periodically. Right now, minecraft was MIA in our gaming rotation though due to this bug.
 

Do you need me to upload worlds again? I think the minecraft scenario “The Mountain” is a much faster repro than the vanilla world. It truly is very quick to show the error. (see other comment). If it’s a matter of “our testing lab for switches isn’t on the eshop so we can’t download that”, I can attempt to generate a more trivial procedure to reproduce the error.

If you believe this error was specifically, intentionally remedied in a version (which I can download on a switch), I will test it.

If you believe this may be related to mesh networking/eero (even though we saw it on simple wifi too), I likely can find three iOS or desktop OS or a chrome OS version and try to reproduce it, but I’d need a little guidance to make sure I had an equivalent version.

And as to eliminating the chance of bad RAM/radiation/high elevation on one of our three switches: We are only about 1000ft above sea level.

We see crashes only in places in other games other people report crashes. We see them all at the same places in games, including when not playing networked games. (Like Dead Cells only crashes at load screens that are widely reported for crashes, or upon specific unlocks which crash other people). Most games never crash. (We definitely understand how unreasonable of an expectation that is for a game the age of minecraft)

We live in a place with low radiation brick, in a brick house (which lowers cosmic ray interference from the side) and almost never have radon in basement’s in our area. We are friends with professional radiation maintenance workers and the last time a geiger counter was in our house there was not incidental radiation (for fun, not because of contamination).

Our Switches are powered through surge protection if not surge protection and battery backup. Power interruptions are rare and uncorrelated with the issue.

I have not done switch development, but, if the switch allows attachment to arbitrary processes by a debugger, and you let me know, happy to do so or setup a VM on a local machine you can remote desktop into and control. If anyone on the MC team is in the Microsoft building on 17th street in Atlanta by Atlantic Station happy to bring down the switches in person to demo it for them (or hell, have a visit at my home if they care, it’s not far).

If I seem overly interested in getting y’all a reproduction: It’s clearly the hard part, both technically and “business decision” wise. I believe this is a QOL issue for switch players which effects “low to medium” revenue customers, the exact ones who are most experimental with “low cost and microtransaction” games. I don’t want competitors to become the default everywhere, etc, because y’all start missing the low spec but still current generation consoles and the like, but I bet whatever changes causes this issue likely advanced some other business or development goal, but not with the intent to disable this capability.

Can I get other players who are on three switches but have problems to try to do the mountain scenario to confirm for the devs how quickly they can generate the same error messages I showed? It’s a truly fast reproduction of the error. Less than an hour.

I’m severely disappointed by this bug and I never would have bought minecraft bedrock edition if I knew it was experiencing such a detrimental bug. Why even have a game released that does not work? Bedrock edition should be taken down until further notice and I want my money back. I have been a long time minecraft player both Java and Bedrock. My friend who is a noob to minecraft and I started a world recently. Simple, easy, vanilla survival world, and single player or split-screen play worked fine. But only a week into the world as the world began taking more MB and as we started connecting using two different Nintendo switches or iOS and a switch it has become UNPLAYABLE. UN. PLAY. A. BLE. I am disconnecting from the game every 30 seconds to a minute. I have searched the internet and have not found anyone reasonably addressing this but I am glad I found someone who is. Our nintendos have over 2GB of space. Our internet connection is pristine and crisp, 5ghz 40+mbps upload and download speed, nintendo online works fantastic with all other games EXCEPT MINECRAFT. The game will lag as soon as I try to open a door or a chest I can tell I’m about to get kicked out because itll open the door or break the block but I wont hear the sound it makes and then oh “disconnected from server” EVERY 30 SECONDS. Please for the love of god give me my money back and take the game down til it works

I've been following this bug for some time, and a recent email about a new comment reminded me that I found a solution, so I figured I'd post it here in case it helps others.

I was experiencing this bug since 1.20 (Trails and Tales), but ever since I bought a Realms subscription this issue disappeared completely. Realms offer a lot of benefits (like automatic world back-ups and letting friends or family play while you can't), but as this is a paid solution, I understand it's not for everybody.

This bug does occur on all devices it seems. From what I have been experiencing, especially lately, the bug seems to occur in the areas that have been massively edited by the player. Could this issue be a data save issue or an issue with how the game loads in the world? If so, it could explain the common lag issues in those areas specifically and why the player keeps getting disconnected from the client. It also could explain why those with great processors and internet speeds still experience this gross amount of lag. The game itself is unable to process the changes properly. I would love for this to be marked high priority. Dear Mojang has been making lots of wonderful changes under the hood so to speak, so I imagine the save and load process might need some tweaking to compensate. I have no complaints if they dedicated a whole update for this fix!