Checklist (07 - Lists) source code crash on list select

I’m having issues with my app crashing about half way through the Checklists tutorial.
It started sometime for me while building from the equivalent of the source code file (06 - Saving and Loading) but before I was at the completed level of (07 - Lists).

Basically somewhere between p.146 and p.172 of the second tutorial, but I can’t figure out where.

So I loaded up the provided source code for “07 - Lists”, but it still crashes on me every time I tap on a list from the main page. I haven’t modified this Xcode file at all. This is what came with the tutorial.

The error happens in AllListsViewController.swift at the LoadChecklistItems() method.

This is the line where the error occurs…
items = unarchiver.decodeObjectForKey("ChecklistItems") as! [ChecklistItem]

This is the message I get in the debugger…
fatal error: unexpectedly found nil while unwrapping an Optional value (lldb)

Anyone come across this?
I don’t understand debugging and error correction enough to fix my own code yet, so I want a clean build to use from this point on before I come back to it. However, if the provided code is bugged, I’m stuck.

I just went back and checked the source code from “06 - Saving and Loading” and get the same error, but it happens when it first tries to run the app and crashes right away.

This is strange because MY build up to that point worked fine.

Make sure you remove the Checklists.plist file.

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That fixed it for both apps. Thank you so much for your help! :slight_smile: