There are many occasions when you try to open an .xls file from the forum and you get an error.
Such as this thread.
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Open the file location to see where the file is and it looks fine.
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In file explorer, select the "View" tab then check "File name extensions".
You will see ".xlsx" has been added to the end.
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Remove the ".xlsx" extension. Select "Yes" to confirm you want to remove it.

Open the file.

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