single player, survival mode, difficulty normal, savanna plateau, living in structure under a waterfall which has been redirected using cobblestone, stone and stone slabs (these blocks create the ceiling of the structure)
1. Crafted new item frame
2. Crafted Diamond Helmet
3. Enchanted Helmet (unbreaking 1 and aqua affinity)
4. Placed item frame on vertical wall immediately below ceiling
5. Placed Helmet in item frame
6. Changed my mind (did not look good!)
7. Removed helmet from item frame with iron pick axe
8. Helmet leaped into ceiling and disappeared! Also not in hotbar or inventory (five diamonds and experience points gone!)
9. Removed ceiling slabs and blocks searching for the helmet
10. Flooded the place but could not locate the helmet
11. Going back now to fix the flood damage!
Related issues
Comments


I have had this happen to me in 14w30c. Very rarely in small rooms (low ceiling, narrow hall, etc) item will pop off frame and then just disappear never to be found again.

I just had this happen in 1.8-pre3. I had five item frames on the wall with maps, and wanted to move them elsewhere. When I hit them, I only obtained three frames and three maps; two had vanished. I searched all adjacent areas with no success.

Can anyone provide exact steps to reproduce? There seems to be something that rarely happens that causes this.

I have a crowded room 2 blocks high with three item frames. Since I updated (I don't think I had a choice) to 1.8 I am not able to retrieve items from these frames, or the frames themselves. They just fly away for three or four blocks when broken, then disappear. In 1.7.10 I could see them falling to the floor, then retrieve them. I regret the release of 1.8 .....

I can confirm this has happened to me several times. In each case, the frame was near the top of a 3-block high room. Items removed would fall to the floor or up to the ceiling and then disappear.

The pattern I am seeing is item frames 1 block below a ceiling made of solid blocks. Still can't reproduce though, there must be some kind of extra condition.

Here's vertical cross section of the room where this occurred:
Layer 1:
SSSSSSS
SSSSSSS
SSDDSSS
SSDDSSS
SSSSSSS
Layer 2:
SSSSSSS
AAFAAAS
AFAAFAS
ACAACAS
SSSSSSS
Layer 3:
SSSSSSS
AAAAAAS
AAAAAAS
AAAAAAS
SSSSSSS
(S=stone; D=Door; A=Air; F=Frame; C=Chest)
Item that disappeared was a Diamond pickaxe with Fortune II. The room is underground at y=8, so the stone floor and ceiling extend down to bedrock and up to ground level.
Steps:
1. Place item in frame just under the stone roof
2. Left the chunk for some time
3. Returned. Left-clicked frame to release item.
Item fell to the floor in the corner at the bottom right of the cross-section and immediately.

I finally found the cause of this issue. When an item gets stuck in a block, Minecraft automatically pushes the item upwards to free it again. Your bases are underground, so whenever an item gets stuck in the ceiling, you can find it back at the surface, even if the surface is 200 blocks higher. As soon as you arrive at the surface, the item is already despawned. This means that the bug here is not the items despawning, but the items getting stuck in the ceiling. MC-4 is similiar to this.

My items fall to the floor, then disappear. I can only retrieve them by breaking the block the frame is attached to. Then both the frame and item don't fly but just fall to the ground.

I believe StevenNL2000's last comment is correct about the cause of this problem.
In my base's storage area, I have two 3-high rooms separated by a floor/ceiling of 1 block of stone and item frames on the highest block in the lower room.
Removing the item from the frame shows the item ejecting from the frame and disappearing when it hits the ground. I went and checked the upper room, and yep, there the items were, scattered on the floor. I was able to pick them up normally.
While I don't think it matters which item is in the item frame, I was working with: redstone dust, slime blocks, and slimeballs (v1.8).
Given how many votes the other issue has – yet it isn't fixed, probably because it would break a bunch of popular game mechanics – I would tend to think that this might better be fixed by adjusting the direction and/or speed the item is ejected from the item frame so it doesn't collide with the block above.

This is caused by the item frames going through the ceiling, making this a duplicate of MC-3706, which describes that problem.

I emphasize that my items fly to the floor, not the ceiling, then disappear. The frame hangs high in a 2-high room.


Yes, thanks.
I followed your steps, but the helmet did drop for me. Can you post what exactly is needed to reproduce this bug?