Although you think this is raw data, it's not. The mere fact of you getting it into Excel means that it isn't; Excel has tried to be helpful by converting text to real dates, and what it thinks are days and months depends on the locale that Excel is set to.
If the textual dates are not the same as the locale that Excel is set to then Excel changes what it can, getting the months and days of the month wrong, and those that it can't convert (because it looks to Excel that the date, say, has a 14th month) then it gives up and leaves it as text. This means that it's very likely that any 'conversions' to dates are ALL wrong (except for when the month and the day of the month are the same - as is the case in cells B3:B4 of tyour 'raw' data sheet).
So instead of bringing the data into Excel and later processing it with Power Query, you should bring the data into Excel using power Query.
I don't know where your data comes from (do you cut and paste? open a .txt file, a .csv file?) and it's this which determines the best course to follow when bringing this data into Excel.
Traditionally, if it's cut and paste, the solution is to start by formatting the cells which receive these data as
Text before pasting. This is a nuisance because you don't always know how big a range of cells need to be set as text before you import it.
More recently, newer versions of Excel seem to allow you some options on automatic conversions as data is brought in, but it doesn't seem to be enough:
![1703862443516.png 1703862443516.png](https://chandoo.org/forum/data/attachments/86/86129-f66d27456e24b333d3c628768c50aad1.jpg)
If you disable the highlighted option above, and hover over the information symbol (circled) you're told:
![1703862711002.png 1703862711002.png](https://chandoo.org/forum/data/attachments/86/86130-e8f382959eea63155f14ba74600aadf3.jpg)
and with me, this is true since Excel does try to convert your date strings.
So the question is, where is this data before it hits Excel?, and if it's a text or csv file or some such, attach it here and we'll be able to show you possibilities to import the data correctly.