By default, Microsoft Excel has error checking that will place a warning indicator next to all cells that have numbers in a cell formatted to be text. It’s common to have serial numbers and other entries that will contain text and numbers in the same field, so having a warning about it is unnecessary.
To disable this and turn it off, in the Mac version, go to the Excel Menu and choose Preferences > Error Checking > and remove the check next to “Numbers formatted as text” as shown below.
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