Remove any left/right justification from that column. Numbers will be ranged right, text ranged left.


Unfortunately, when you open a .csv file with dates in Excel (the same applies to pasting data), Excel tries to be helpful and converts what it thinks are dates into proper Excel dates. There are problems with this; it makes assumptions about the order dmy/mdy and those assumptions can often be wrong - it depends on your locale and the locale that the csv was created in. Some dates, eg. 2/1/2023 could be interpreted 2nd Jan, or 1st Feb, one of them is wrong. If the csv file has been created in a dmy system and is loaded into a dmy Excel there should be no problem. I believe the csv file was created in a dmy format and is being loaded into a dmy system (Dublin?) so it's a bit surprising that some are failing to be converted to dates properly. In this case I'd look more closely at the csv file using other means (Notepad) to see what could be going wrong (are there some extra spaces lurking?).


Use Power Query (Get & Transform Data) to import the data, it doesn't try to interpret the dates and you'll be able to do the various transformations including conversion to proper dates



How do you do this? In what application?


If you want, send me in a Private Message here (I suspect you don't want the data in the public domain) the actual untouched csv and I'll write (actually, no writing, just clicking, to create) a bit of Power Query code to handle the import of future csvs.