We have a clear opinion on this discovery: the difference between `#N/A` and `NA()` is more than a stylistic quirk, it is a meaningful lever for controlling how Excel surfaces errors to you. The user who posted this observation has found something that most spreadsheet veterans have missed, and it deserves attention.
Here is what matters in practice. When you use the `NA()` function inside a formula, Excel appears to suppress the green error-corner indicator on cells that return `#N/A`. This is not a bug; it is a deliberate behavior tied to how the calculation engine evaluates the function. If you use the literal `#N/A` instead, the green corner appears as expected. The distinction is subtle but powerful. For anyone building large arrays or complex `LET` formulas, choosing `NA()` over `#N/A` can clean up your worksheet visually by hiding the error flags on cells that are intentionally returning a missing-value marker. That is a real productivity gain when you are dealing with 9,900 `#N/A` results in a single array.
The user also notes a secondary benefit: wrapping `#N/A` in an array literal, like `{#N/A}`, lets you return a mixed array without the entire formula collapsing to a single error. `=HSTACK(1,{#N/A})` gives you `{1,#N/A}`, while `=HSTACK(1,NA())` or `=HSTACK(1,#N/A)` returns only `#N/A`. This is a concrete, repeatable technique for anyone who needs to preserve structure in their output. It is not a theoretical edge case; it is a direct solution to a common frustration.
What this means for you is simple. If you have been using `#N/A` out of habit, you now have a reason to reconsider. The `NA()` function gives you cleaner error handling and more control over how your spreadsheet communicates with you. The performance angle the user raises is worth testing in your own workbooks, especially if you build large arrays. The evidence here is clear: the function call matters, and the green corner is not arbitrary. Use `NA()` when you want quiet, intentional errors. Use `#N/A` when you want the warning. Pick the tool that fits the task.