How to reproduce it:
- Prepare to send a message.
- Attach something to the message. (This reduces your carried weight, although it isn't shown.)
- Put more stuff into your inventory so that you no longer have enough free weight to hold the attachment.
- Try to retrieve the attachment, or cancel the message, or replace the attachment with something else (weight doesn't matter).
- Congratulations! You've just lost your original attachment.
The bug is in step 2, when the game reduces your carried weight. At one point (starting about 4-5 months ago) it did not, but the fix was reverted sometime afterward for unknown reasons. Putting more items into your inventory subsequently can leave you with a weight limit that is insufficient to hold both your current inventory and the pending attachment. Then, if you try to recover the attachment, the game attempts to put it back into your inventory and fails, and the attachment is lost because the game designers did not anticipate this possibility.
What's the glitch that people keep talking about?
After you select to use storage and close the Kafra dialog, there is a brief window before storage opens during which the mouse cursor is unrestricted. If you click on the mailbox NPC during this time, you can use the mailbox to receive messages while storage is open. This allows you to receive messages continuously without repeatedly paying mail and storage fees but does not otherwise enable any functionality that is not possible through other, uncontroversial means. Most importantly, it is utterly unrelated to the bug described in this post because (1) the bug cannot occur except when you are sending mail, not receiving it; (2) to send a message when storage is open, you simply need to click on the "Send Messages" button in the friends/party window which, by the way, has never been restricted with respect to simultaneous storage use; and (3) triggering the bug requires only that you acquire weighted items from some source, but this source doesn't have to be storage; it could be a trade or even another mail message. This is important and I suspect some people will not even bother to read this paragraph in full, so here it is again: the glitch has absolutely nothing to do with the bug!
Why would you try to "overweight" yourself?
No one does so intentionally; rather, it can happen unexpectedly for a variety of reasons. Several of them are presented in the following annotated videos.
Video #1 is a reenactment of how someone lost items while sending a message to me.
1. She attaches a few thousand of the same item.
2. She learns my weight limit is higher than what she'd thought.
3. She pulls more from storage without checking her stats, expecting the game to reject the transfer if it would lead to problems. (It doesn't, which is the bug!)
4. She tries to stack the inventory items with the attachment, but this doesn't work--it replaces the attachment instead. This may not be serious enough to be considered a bug in and of itself, but it's still bad because it is inconsistent with what experienced players have come to expect after extensive inventory/storage/cart management.
5. The game first tries to transfer the attachment to inventory. That obviously fails, so the attachment is gone.
http://www.youtube.com/watch?v=e0Beoh_Cn4E
Video #2 shows how I lost my items. The annotations are fairly thorough so I'll forgo explanation beyond one comment that isn't mentioned in the video: When you successfully send a message, your only feedback is a one-liner in the chat window telling you that the message was sent. When you're sending many items and many messages, it can become virtually impossible to match the lines with the corresponding messages. That is what happened to me.
http://www.youtube.com/watch?v=hTTw6TkAKrg
Video #3 shows how you can lose items using ONLY the mailbox NPC and nothing else.
http://www.youtube.com/watch?v=2JYO8cBFVZQ
Another reasonable scenario, similar to #3, is item remailing. By that I mean opening mail from someone, getting the attachments, and resending them to someone else. If you fail to notice that a message wasn't sent (much like in #2), then pulling more items from another message in your Inbox produces the same result--you lose items, all while using the mailbox "as intended"--no storage, no party/friends, etc.
Some other useful corollaries are:
- Never try to send items when you're overweight (>100%). You can go overweight by dismounting, or by moving a TKM from an aligned map to a non-aligned map. These are just some obvious examples.
- Although I've been focusing on weight limit, you can probably lose items by exceeding the hidden item count limit. I haven't tested this.
- The devs need to put more thought into user-friendly design. In all of these examples at least one instance of poor design was implicated as a catalyst for the ensuing disasters.
Edited by renouille, 05 May 2011 - 12:30 PM.