0. ALWAYS PROVIDE INFORMATION ABOUT MODLOADER (Fabric / Forge) AND MOD VERSION (For Example 1.19.2-8.2.10)
   -Fabric
   -1.21.1
   -Modrinth launcher
   -Singleplayer
   -Traveler's Backpack version 1.21.1-10.1.15 (also occurred on version 1.21.1-10.1.13)

1. Describe the bug
   Unable to open backpack (on ground or on back). Game doesn't fully crash but will immediately exit singleplayer world with ""connection lost, network protocol error" and brings me to multiplayer server list menu.

2. Write steps to reproduce the bug
   Open backpack on ground or on back
   -backpack is full, has tanks and crafting upgrade applied and is iron tier
   -I have other mods installed, however I think only vanilla items are in the backpack (some spaces are obstructed via tooltip and there isn't enough time to look before the game exits)

3. What is expected behaviour
   Game does not exit

4. Screenshots (If applicable)

disconnect-2025-02-17_15.24.22-client.txt

I need log, cant do anything without it

Sorry, I meant to attach the log. Empty backpack with same upgrades does not seem to cause the issue

Does anything significant happen when you first encountered this issue?

Does anything significant happen when you first encountered this issue?

The only thing I can think was that I was reorganizing chests and using TerraStorage "loot all" and "deposit all" feature with the backpack. Though I was able to do this multiple times before encountering the issue, and issue hasn't started until today.

Not sure if this video helps

I need log, cant do anything without it

Also need info if opening empty backpack causes the same crash

Could you use mod like Component Viewer and export this backpack components (data) and upload it here so I could investigate the issue?

https://modrinth.com/mod/component-viewer/versions

item_stack_components.txt

Component Value:
{
modifiers: []
}

Thank you I'll investigate issue when I get home. I think you can try upgrading to another backpack tier and it should resolve your problem as of now. You can also try shift + right click on placed backpack with blank upgrade in hand to reset backpack tiers. Just be careful it will shatter all items from your backpack around.
Im not closing this issue as of now.

crash will be fixed, but I do not guarantee that terrastorage will work properly, currently the crash occurs because terrastorage put item that is not an upgrade into the upgrade slot

crash will be fixed, but I do not guarantee that terrastorage will work properly, currently the crash occurs because terrastorage put item that is not an upgrade into the upgrade slot

Okay! Thank you for looking into it. I feel silly now... It always crashed before I had time to see what was in the backpack/where. Sorry for the trouble, and thanks for everything you do to keep this mod updated! <3