So...it's taken me several hours to pinpoint this, but it started after the last update. I have tried deleting the config and re-disabling the mobs I had disabled, but this problem persists with the Rocket Creeper set to false.

I did check it several times, so I can say with fairly high certainty that this is the cause. It happens on both singleplayer worlds and on our multiplayer server.

[Server] Server thread/WARN [minecraft/EntityTrackerEntry]: Fetching addPacket for removed entity
spammed over and over in the console.

Sigh. Seems to be still doing it even with Rocket Creeper enabled, contrary to my previous tests results. I guess back to the drawing board. :( I'll report back again if this turns out to be caused by PM for sure.

Possibly also related to the Grove Sprite sapling placing setting being set to false? I'm still testing....

OK...so it seems like it's doing it when the Rocket Creeper is set to false, and also when the Grove Sprite saplings setting is set to false. ¯\_(ツ)_/¯

If I find out something different, I will report back again.

One last update, then I'll leave it be till you can have a chance to look at it. I'm still occasionally getting the error, but nowhere near as much. I'm wondering if it's also the Brain Slime that I have disabled that is causing the problem? I'm going to bed now so I can't test it further right now, but will report back later tonight when I get time to check it.

Sorry for the trouble. I have not heard this one before so I'm curious. What if you also put the spawnAllowed for all those entities to 0? Does that solve it maybe? Hmmm, thanks for the report!

Ok so....I don't want to get too excited about it, cause every time I think it's fixed, it's not fixed. But it seems like setting the spawn weight to 0 in multimob gets rid of this error. It may be a combination of setting the spawns for the mobs to false in both PM and MM config on top of setting the spawn weight to 0. Not sure, but at least you know now what is (probably) causing it.

I would like to suggest removing either the "mob activation" true/false in the PM config -OR- the "spawn allowed" true/false from MM, since they basically do the same thing and it's redundant to have it in both configs.

OK....so back one last time to verify that I have not seen the error again since setting the spawn weight to 0 on the disabled mobs. I also have the sapling planting turned off, so that was obviously a correlation that did not turn out to be a causation in the end.

So to clarify, based on my observations:

1. the error is not caused by any specific mob being disabled
2. the error persists when setting the desired disabled mobs to false in the "spawn allowed" section of MM config and/or the "mob activation" section of the PM config
3. the error stops when setting the spawn weight of the disabled mobs to 0 in MM config (only tested with both the MM and PM configs for mob spawn/activation set to false for disabled mobs...the error may or may not return with one or the other set to true with spawn weight on 0...i did not test this part)
4. the error is not caused by the setting to disable grove sprite sapling planting

Thanks a lot xAlicatt! I think I already see whats the problem. Cheers!

The problem with doing that with the Grove Sprite setting though is that I don't want to disable the mob spawning, I just want them to not be able to place saplings :P I will give it a try though and get back with you on it.

It looks like an entity is forcefully being removed while sending a packet to the server. Currently Im having a hard time thinking of why that would happen; but one reason I can think of would be disabling a mob in PrimitiveMobs but still trying to have it spawn? (although that should technically be impossible) as it will then immediately remove the entity, but again that SHOULD be impossible. I can do a bit of digging but probably cant debug this until I know what's different on your end :(

It's probably (possibly) the configs with the disabling of spawning of the mobs being in both Multimob and in Primitive Mobs. Maybe something between the two is conflicting...so Multi is trying to allow them to spawn, but PM says no they can't spawn. I don't know what difference that would make with the saplings setting, but that could have just been me misinterpreting the results of my test...since it's extremely unscientific :P.

I'm testing more now to see if the spawn setting theory is possibly the cause. Will report back once I know something more concrete.

Have you not been able to recreate the issue? Afaik I do not have any other mods that affect mob spawns.

Just to say Ive been getting this too and was trying to work out where its coming from, thousands of lines in logs like this

Im also getting:
[14:47:28] [main/WARN] [minecraft/NetHandlerPlayClient]: Received passengers for unknown entity
[14:47:28] [main/WARN] [minecraft/NetHandlerPlayClient]: Received passengers for unknown entity

Removing an entity in the PM config should no longer cause these errors with the newest MultiMob version. I hope ;) the passenger thing is one I have been hunting forever and still have not found the proper cause.

Log message? Which log message? The passenger one? That is vanilla code sadly. You are getting spammed? I only get that log every so often ,very rarely even.

Could you disable the log message? It fills the log to such an extent that MultiMC just shuts down

Thanks man will try that and report back

Yep, that worked no spam in logs anymore - thanks for the advice - had missed the "0" bit

This should have been fixed... darnit. At least you have a temp fix. But afaik there should be no way the entity spawns when disabled. More going down the rabbit hole I suppose

Ok, so with latest PM and MB im still getting hundreds of these:
[19:21:45] [Server thread/WARN] [minecraft/EntityTrackerEntry]: Fetching addPacket for removed entity
[19:21:54] [Server thread/WARN] [minecraft/EntityTrackerEntry]: Fetching addPacket for removed entity
[19:21:54] [Server thread/WARN] [minecraft/EntityTrackerEntry]: Fetching addPacket for removed entity
[19:22:01] [Server thread/WARN] [minecraft/EntityTrackerEntry]: Fetching addPacket for removed entity
[19:22:01] [Server thread/WARN] [minecraft/EntityTrackerEntry]: Fetching addPacket for removed entity
[19:22:01] [Server thread/WARN] [minecraft/EntityTrackerEntry]: Fetching addPacket for removed entity
[19:22:10] [Server thread/WARN] [minecraft/EntityTrackerEntry]: Fetching addPacket for removed entity
[19:22:10] [Server thread/WARN] [minecraft/EntityTrackerEntry]: Fetching addPacket for removed entity
[19:22:10] [Server thread/WARN] [minecraft/EntityTrackerEntry]: Fetching addPacket for removed entity

The only config ive attempted to change is the PM one to disable rocket and festive creepers

@MohawkyMagoo but that's what's causing the error to spam. If you have only set them to false in the Primitive Mobs config, they will cause the error spam.

If you go into the MM config and look under "spawn allowed" and set the ones you want to disable to false. Then scroll further down to "spawn weights" and set the ones you are trying to disable to 0.

This stuff may be changed in the newest version...i haven't downloaded it yet...but this is how i got rid of the spam in my pack.

Happens on Vanilla 1.14 - so it's a related to one of the 1.14 pre-release changes
[10:41:12] [Server thread/WARN]: Fetching addPacket for removed entity
[10:41:12] [Server thread/WARN]: Fetching addPacket for removed entity
[10:45:14] [Server thread/WARN]: Fetching addPacket for removed entity
[10:45:14] [Server thread/WARN]: Fetching addPacket for removed entity
[10:45:48] [Server thread/WARN]: Fetching addPacket for removed entity
[10:45:48] [Server thread/WARN]: Fetching addPacket for removed entity

@kanoi I assure you, it's unrelated to 1.14. This mod isn't even available for 1.14. lol....

We are getting this log spam and do not have Multimobs install...only Primitive Mobs. How do we turn off spawning of mobs without bogging down the server in log spam?

We are getting this log spam and do not have Multimobs install...only Primitive Mobs. How do we turn off spawning of mobs without bogging down the server in log spam?

You don't...not unless the developer comes back and starts working on the mod again or you know someone who would be willing to fix the bugs for you. But then you wouldn't be able to put it into a modpack if you plan to publish it on Curse, since it would be rejected if the mod is not exactly like the one on their site.

We are getting this log spam and do not have Multimobs install...only Primitive Mobs. How do we turn off spawning of mobs without bogging down the server in log spam?

Also you can't run Primitive Mobs without Multimobs I thought?? Is it not a required library? The only way to keep the logs from being spammed (which I'm sure also causes lag) is to use the method I outlined above as a workaround for the issue.

Oops...NVM then...I'll make the change in the config. Didn't know MM was installed.

I have the same problem when i disable the Traveling Merchant (The trades are way too OP)

I realize this thread is a little old, but this issue is still happening today. I have MC Eternal running on our server and everything was fine until last night when I disabled a few mobs from this pack's config. Lily Lurkers (who ate all my pixies!) and the harpies which nearly enraged my friend into quitting... now, I have set them to not spawn, but instead of just not spawning, they appear to be rapid-fire spawning and disappearing instantly. I sat at the Mangrove and watched it happen. You can see them blinking in and out of existence. Along with this new and interesting spawning of the lurkers, my log is now spammed with that message: [07:54:05] [Server thread/WARN] [minecraft/EntityTrackerEntry]: Fetching addPacket for removed entity
This happens just about once a second, which correlates with the spawning and disappearing lurkers.
My confusion comes with the idea that telling something to not spawn doesn't make them not spawn, just spawns them and then removes them. Is that intended behavior? If so, why? If not, why is it happening?
It's causing an issue with the server and other things are starting to lag and not work.
I don't want harpies and lily lurkers, but I do want grove sprites (so freaking cute!)
Has anyone fixed this issue completely as of yet?
Thank you for your time.

This mod seems to have been abandoned last I checked. The only way to "fix" the problem is to follow the instructions outlined in a previous comment in this thread.

I realize this thread is a little old, but this issue is still happening today. I have MC Eternal running on our server and everything was fine until last night when I disabled a few mobs from this pack's config. Lily Lurkers (who ate all my pixies!) and the harpies which nearly enraged my friend into quitting... now, I have set them to not spawn, but instead of just not spawning, they appear to be rapid-fire spawning and disappearing instantly. I sat at the Mangrove and watched it happen. You can see them blinking in and out of existence. Along with this new and interesting spawning of the lurkers, my log is now spammed with that message: [07:54:05] [Server thread/WARN] [minecraft/EntityTrackerEntry]: Fetching addPacket for removed entity
This happens just about once a second, which correlates with the spawning and disappearing lurkers.
My confusion comes with the idea that telling something to not spawn doesn't make them not spawn, just spawns them and then removes them. Is that intended behavior? If so, why? If not, why is it happening?
It's causing an issue with the server and other things are starting to lag and not work.
I don't want harpies and lily lurkers, but I do want grove sprites (so freaking cute!)
Has anyone fixed this issue completely as of yet?
Thank you for your time.