Strange Behavior in Microsoft Excel

Neddy Bate

Valued Senior Member
I was creating a new spreadsheet when I noticed a really strange behavior in Excel. I have used Excel for decades and never noticed anything like this before. I would love to hear any explanation for any logic that might be behind this.

Follow the steps below to replicate the strangeness for yourself.

Open a brand new spreadsheet and type a simple formula into cell A1 like this:
=1+2

Next, copy that cell down to the 3 cells directly below it, so now the four cells A1, A2, A3 and A4 are like this:
=1+2
=1+2
=1+2
=1+2

Just to the right of the first cell, type the following formula into cell B1:
=A1

Next copy that cell down to the 3 cells directly below it, just as before, so now the formulas in those four cells B1, B2, B3 and B4 are like this:
=A1
=A2
=A3
=A4

And now, to see the strange behavior of Excel, type the following into the cell A5:
=B1

Boom! You should now see that Excel has taken it upon itself to fill in cell B5 with a formula! Why?!?!? I was pulling my hair out thinking I must have had a corrupted spreadsheet, until I finally isolated the cause.

This does not happen if you use less than four rows. It also does not happen if you type in the 1+2 formula manually in each cell, you have to copy them down. I have never seen Excel do anything like this before. Can anyone explain the reasoning here?
 
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At the risk of being glib:
...Excel has taken it upon itself to...
Anyone who has used Excel for more than [JANUARY 13th, 1996!!!] seconds, knows the above phrase well.
There are whole meme templates devoted to things Excel inexplicably takes upon itself.

upload_2023-6-22_20-11-50.png


Don't try to understand, just make a workaround.

.
 
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These replies actually help make sense of it, thank you. It is almost as if there is some early form of AI built into the program. Eerie.
 
Well, except that Excel has been doing this since decades before AI was just a gleam in the eye of a neural net developer...
 
Well, except that Excel has been doing this since decades before AI was just a gleam in the eye of a neural net developer...

doing this

Do you know of other instances where Excel inserts its own formula into an otherwise empty cell?

The example you gave about Excel interpreting "1/2" as "January 2nd" happens within the one cell where the data is typed. Not a completely different cell.
 
Do you know of other instances where Excel inserts its own formula into an otherwise empty cell?
Not that explicitly. Excel is very opinionated about what it thinks you meant. It will aggressively, proactively take steps.
You particular flavour seems to at least loosely fit that bill.

But trying to sort out the details seems a bit like trying to sort out why this Wolverine is currently chewing off your leg with its molars when they usually they chew off legs with their incisors. If you see what I mean.

Anyway, I'm not sure I can contribute meaningfully further. Or frankly, if I have yet.
 
Not that explicitly. Excel is very opinionated about what it thinks you meant. It will aggressively, proactively take steps.
You particular flavour seems to at least loosely fit that bill.

But trying to sort out the details seems a bit like trying to sort out why this Wolverine is currently chewing off your leg with its molars when they usually they chew off legs with their incisors. If you see what I mean.

Anyway, I'm not sure I can contribute meaningfully further. Or frankly, if I have yet.

Wolverine chewing off my legs?!?!?

This is about as relevant as Excel putting a formula into one of my empty cells
 
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