Here are some notes on IndexOutOfRangeException and ArgumentOutOfRangeException:
Steps to success:
- find which collection it is and what line of code accesses it <— (critical first step!)
- find out why it has fewer items than you expect
- fix whatever logic is making the indexing value exceed the collection size
- remember that a collection with ZERO elements cannot be indexed at all: it is empty
- remember you might have more than one instance of this script in your scene/prefab
- remember the collection may be used in more than one location in the code
- remember that indices start at ZERO (0) and go to the count / length minus 1.
This means with three (3) elements in your collection, they are numbered 0, 1, and 2 only.
For future reference, if you post a code snippet, ALWAYS USE CODE TAGS:
How to use code tags: Using code tags properly