Potential Workaround
As the most recent reports of this issue appear to be coming from players using single player mode, players that want to start a new save may benefit from starting a private multiplayer save and playing solo. The only difference in these saves is your username appears in the bottom left and the label maker does not work in multiplayer.
I know this isn’t ideal, but I hope it may be of some help to the community.
[Edit: I’ll add this to the top post for visibility too]
Hello, for my part I have recreated a part. I am day 29 and so far no problem with saving. I have explored 6 islands and no problem. I was careful not to have any object next to my cabin when saving. I hope it will continue like this
XBox Series X
New player and this “cleaning up” bug happened two days in a row.
The first time while saving I was moving the controller stick around. (11/29/21)
The second time, thinking I was smart, made sure to not move anything. However I saved after my controller had been idle.
Hope this helps and looking forward to a patch for XBox X
Fun game, once you get past the frustration of all the gaming time lost. 
I’ve had the same problem on PS5 - Singe Player Mode.
When I managed to beat the thirds boss (the squid) I climbed on to my raft and saved using the sleeping bag. The game slowed down and froze completely, after which I quit the game. Also, the trophy for beating the three bosses didn’t pop.
One interesting thing I noticed is that when I look at the world editor, my player seems to be at the central island. Before the crash, I successfully saved 2 blocks away from the island, where the boss was. The crash also happened 2 blocks away from the central island.
Hi all, quick update for you…(I’ll add this to the top post too)
UPDATE 01/12/21
The team have replicated the issue triggering when a full crate is dumped into the deep ocean (as reported by a number of members of the community). They’re now working with these reproduction steps to find a fix.
However, I am aware there are a number of players who have reported different reproduction steps that they have replicated themselves and players who have not dumped crates into the ocean. As there may be multiple triggers for the issue I’m going to continue to gather information for the team and let they know the details of what players are experiencing.
Thank you to everyone who has reported their experience so far. The team are very grateful to the community for sharing what information you can about your experiences with this issue.
@NB2021deep - please feel free to send your files via wetransfer, this should be no problem. I will retrieve them and pass them onto the team. Please tag me or send me a PM when you send them so I know to look for them. Please also note that files cannot be fixed and returned but your files will be used to continue investigating this issue.
@S0uhh - Thank you for that update, if anything changes (though I hope you continue to avoid this issue) please let me know.
@DJpapa78 - Welcome to the forums, thank you for sharing this information. I will make a note of this for the team. Can you confirm for me if by “idle” you mean the controller disconnected / turned off and you turned it back on? Or do you mean to didn’t use any buttons during the save?
@Elessar8 - welcome to the forums. Thank you for sharing your experience. Saving after beating the boss is a common report I’ve seen from players. I’ll add your experience to my report for the team. Do you recall if you lost any weapons or items during the fight? Or spears that might have missed and fallen past the boss?
I think the trophy you’re refering to is the call me ahab trophy, but I believe this unlocks when you craft one of each boss trophy. However I did see another report today on this issue and will make a note of your experience on that report too.
Regarding the position of the cartographer, this was mentioned by another player. It is interesting you have seen the same thing and it’s good to know for the team that more than one player has seen this.
Hi Clare, thank you for your reply, your responses and the effort from the devs are appreciated!
I lost a lot of items in the fight, I think probably 10 spears missed the boss.
I also am I new player and just last night as I was saving on a new island my game froze. I restarted my Xbox one but I cannot get back into my game. It’s stuck on the loading screen.
Idle meaning it disconnected after I stepped away to do some other things.
When I came back and connected the controller, I went to save before I was going to turn it off, then the bug occurred.
Hope that helps.
Thank you all, I’ve added this info to my report 
This workaround hasn’t helped me, I’ve lost two games so far. So started a new game keeping all items further away from shelter and in chests. Went to save a game on the third island I’m exploring AND frozen. Again, stuck in cleaning up.
Just had the same thing happen, 5days in and stuck. Restarted again and made it 11 days. Saved, notice said game saved, whole thing froze so I hard closed the game and now I can’t get in again.
I restarted and after 10 days (time of the game not actual time), I saved on my shelter and again the bug…I don’t play anymore, I’m waiting for a fix.
Xbox One fully updated-Game version 2078
Third island, one island NE of starting island, small island-no snakes or boars
Tent placed so I am looking out to sea when I save. Nothing on the ground in front of me, everything placed behind me to try to avoid crash upon saving.
No good!!! Froze/crashed when saved, loading stuck in cleaning up phase.
A couple things that I noticed…
The save notification does pop up in the lower left portion of the screen when it freezes.
Cartographer shows me on center/starting island. I was one island to the NE of that island.
I was mining clay that day and I did have one chunk of clay roll into the abyss before I could grab it.
I can throw a spear at a palm frond that is on the ground by my smoker and the palm frond disappears. I can target the palm frond under the sand, but not pick it up. It slowly migrates to the edge of the water, in the direction of the current, and then reappears and I can pick it up.
The Night Snakes on the second island that i visited, a large island, do zero damage and do not poison me. I spent ten minutes stomping around on one of them to make sure that I wasn’t just getting lucky. I have not been playing long, and I don’t remember if that is normal.
Really like the game. Got a buddy hooked on it too, he is also having the saving/crash problem.
Have you also had boar/hogs run off into the reef? I’ve lost a few that way they run off underwater and hide in the coral. I found one three days later while I was swimming back from a wreck, it was stuck and I speared it lol.
I have seen snakes and the smaller piglets hiding from me in the shallow water also. If I am short one snake or piglet, I go swimming for them.
Thank you everyone for keeping me updated with what happens in saves you try. If anyone experiences this when trying the solo multiplayer workaround please let me know as so far it appears to be single player that’s affected.
@CorvusCorax welcome to the forums and I’m sorry to hear this workaround has not worked for you. Thank you for letting me know. Before this issue occured for you, do you recall losing anything in the ocean when traveling to or near the edge of the water on the third island or would you it a standard arrivial and save before the issue triggered?
@Spacecoyotey - welcome to the forums and thank you for sharing all of that information. I shall add it to my report for the team and I’m going to submit some unique reports on the issue with the spear pushing the frond under the ground and the night snakes not poisoning or attacking you. Please let me know if you changed the wildlife settings at all.
Thank you also for letting me know that the the workaround of not having items around did not work for you. While I’m sorry to say this is the case, knowing what does and doesn’t work across players helps in narrowing down issues.
Wildlife settings have not been changed. The only things that I have altered are the look speed, inverted axis, and music volume.
Just to clarify, the snakes do attack/strike at me, they just don’t cause any harm.
I forgot to say that this is also a single player game.
Thanks for responding so quickly @Spacecoyotey and for confirming that info for me, I’ll make sure to include it when updating my report for the team today.