Tommy,

These rogue dates that won't format may be text that look like dates. If we
have one of these in A1 try this formula

=isnumber(a1)

which should evaluate as TRUE. If it evaluates as false then it's text.

The fix depends on what is actually in the cell but you could try putting a
1 in an empty cell and copying it then select these 'dates' paste special -
multiply - OK
--
Mike

When competing hypotheses are otherwise equal, adopt the hypothesis that
introduces the fewest assumptions while still sufficiently answering the
question.


"Tommy" wrote:

I receive data everyday with the dates in the following format - 1/12/2025
(dd/mm/year), however I'm trying to format it to the following format-
01-Dec-25.

The option is available under formatting, but the majority of the dates in
the column I select don't format properly. I can't figure why this happens...

Can anyone offer a suggestion as to how to format so the entire column
formats?