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  1. Minecraft (Bedrock codebase)
  2. MCPE-21416

Mobs and Entities can despawn randomly

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    Details

    • Type: Bug
    • Status: Reopened
    • Resolution: Unresolved
    • Affects Version/s: 1.16.210.54 Beta, 1.16.210.53 Beta, 1.16.210.51 Beta, 1.16.100.60 Beta, 1.16.100.58 Beta, 1.16.100.57 Beta, 1.16.100.56 Beta, 1.16.30.52 RTX Beta, 1.16.100.55 Beta, 1.16.100.54 Beta, 1.15.0.11 RTX Beta, 1.16.100.53 Beta, 1.16.100.52 Beta, 1.16.100.51 Beta, 1.16.100.50 Beta, 1.16.20.54 Beta, 1.16.20.52 Beta, 1.16.20.50 Beta, 1.16.0.68 Beta, 1.16.0.67 Beta, 1.16.0.66 Beta, 1.16.0.64 Beta, 1.16.0.63 Beta, 1.16.0.61 Beta, 1.16.0.60 Beta, 1.16.0.59 Beta, 1.16.0.57 Beta, 1.16.0.58 Beta, 1.16.0.55 Beta, 1.16.0.53 Beta, 1.16.0.51 Beta, 1.15.0.55 Beta, 1.15.0.51 Beta, 1.14.20 Hotfix, 1.13.1, 1.14.1 Hotfix, 1.12.0.2 Beta, 1.0.7.0, 1.1.0.55, 1.1.2.50, 1.1.3.52, 1.1.4.51, 1.1.5.0, 1.2.0.22, 1.2.0.81, 1.2.3.3, 1.2.3.6, 1.2.9.1, 1.2.10.2, 1.2.11.4, 1.2.13.10, 1.2.13.54, 1.2.13.60, 1.2.16.3, 1.4.0.5, 1.6.1, 1.8.1, 1.11.1, 1.11.2, 1.11.4, 1.12.1, 1.13.0, 1.14.30 Hotfix, 1.14.60 Hotfix, 1.16.0, 1.16.1, 1.16.10, 1.16.21, 1.16.20, 1.16.50 Hotfix (iOS), 1.16.40 Hotfix, 1.16.61 (PS4), 1.16.100, 1.16.101 Hotfix, 1.16.200, 1.16.201 Hotfix
    • Fix Version/s: None
    • Confirmation Status:
      Confirmed
    • Platform:
      Multiple
    • ADO:
      97757, 112005, 248300

      Description

      Workaround (updated Dec. 5, 2020)

      Since some cases of persistent mobs despawning can be traced to them crossing chunk borders between saves, one way to guard against randomly losing mobs is to prevent them from crossing chunk borders. However, this is not a guarantee or a fix. Positioning mobs away from chunk borders does not mean you will never lose a persistent mob again. Many cases of mobs randomly despawning remain unexplained by the tracker staff and player community.

      Updated description by [Mod] GoldenHelmet July 22, 2020
      This ticket is used as parent for all otherwise unexplained mob disappearances. It covers mobs disappearing related to nether portal travel, long distance single-dimension travel, crashes, realm lag, and any other circumstance, except for the specific circumstances covered by MCPE-66818, MCPE-51837 and MCPE-16863.

      Some random mob despawns can be explained by the mobs crossing chunk borders between auto-saves. Other random mob despawns are reported for mobs that were unable to cross chunk borders.

      I have attached a test world that can be used to reproduce despawning on chunk borders due to a crash with the following steps to reproduce:

      1. Load [EX] Chunk border despawn demo.mcworld.
      2. Press the button to spawn a villager.
      3. Save & quit, then reload, to confirm that the the villager is kept in the world save.
      4. Open the world, flip the lever, and start a stopwatch.
      5. After about 10-15 seconds, close Minecraft without exiting the world (for example, in Windows 10 press alt-F4).
      6. Reopen Minecraft and reopen the test world.

      Expected result

      The villager is still present.

      Actual result

      Sometimes the villager will be gone. I estimate this occurs about once out of 20 attempts. You can see the entire sequence in Chunk border despawn demo.mp4.

      What happens when the villager disappears is that sometime between flipping the lever and force-closing the game, the chunk in which the player is located gets auto-saved and the chunk to the right does not. You can verify this by observing that a honey block is also missing--the fact it was pushed out of the left chunk by the piston is saved, but the fact it was pushed into the right chunk is not.


      Original description
      When I go to Nether and I went back my horses an my animal that I feed is disappear

      Edit by [MCPE Helper] Zeb: When playing on multiplayer, entities can despawn when you travel to the Nether and back to the Overworld.

      Keep in mind that naturally-spawned monsters and animals that have never been interacted with are SUPPOSED to despawn. When testing this bug, please make sure to interact with monsters or animals you're observing first, by tempting them with food, breeding, or name-tagging them. This is not necessary for villagers or iron golems.

      Moderator Note by [MCPE Mod] Dr.Awesome4333: Please only comment New information about the issue.

        Attachments

        1. [EX] Chunk border despawn demo.mcworld
          115 kB
        2. 2017-07-01.png
          2017-07-01.png
          423 kB
        3. 2017-07-01 (1).png
          2017-07-01 (1).png
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        4. 2017-07-01 (2).png
          2017-07-01 (2).png
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        5. 2018-05-12 16.21.12.png
          2018-05-12 16.21.12.png
          2.01 MB
        6. A0113685-1087-4161-97FC-E7C1B54F925D.jpeg
          A0113685-1087-4161-97FC-E7C1B54F925D.jpeg
          1.93 MB
        7. BDED736F-8E02-4616-AD94-B09E0529313C.png
          BDED736F-8E02-4616-AD94-B09E0529313C.png
          1.65 MB
        8. C5A35E2F-73D5-4425-97EA-555BB116E079.png
          C5A35E2F-73D5-4425-97EA-555BB116E079.png
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        9. Chunk border despawn demo.mp4
          5.48 MB
        10. horse_corral.jpg
          horse_corral.jpg
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        11. Horse.jpg
          Horse.jpg
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        12. image-2020-09-10-16-22-17-817.png
          image-2020-09-10-16-22-17-817.png
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        13. image-2020-09-21-15-06-24-519.png
          image-2020-09-21-15-06-24-519.png
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        14. IMG_0122.png
          IMG_0122.png
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        15. IMG_0123.png
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        16. IMG_0137.png
          IMG_0137.png
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        17. IMG_2621.PNG
          IMG_2621.PNG
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        18. IMG_2622.PNG
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        19. library 1.png
          library 1.png
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        20. library 2.png
          library 2.png
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        21. library3.png
          library3.png
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        22. Light levels for Rogue Cheddar despawn room.png
          Light levels for Rogue Cheddar despawn room.png
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        23. Minecraft 6_29_2020 11_01_23 PM.png
          Minecraft 6_29_2020 11_01_23 PM.png
          1.13 MB
        24. Minecraft issues 1.png
          Minecraft issues 1.png
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        25. Minecraft issues Date created.png
          Minecraft issues Date created.png
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        26. Minecraft issues Please do not comment.png
          Minecraft issues Please do not comment.png
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        27. noborder.png
          noborder.png
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        28. NoHorse.jpg
          NoHorse.jpg
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        29. Pigs_Despawning.png
          Pigs_Despawning.png
          1.33 MB
        30. Screenshot_20200522-195543.png
          Screenshot_20200522-195543.png
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        31. screenshot-1.png
          screenshot-1.png
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        32. sheep_pen.jpg
          sheep_pen.jpg
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        33. Untitled.png
          Untitled.png
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