Hi @janderson,
It looks like your numerical values are formatted according to European tradition, where the "," (comma) is used as the decimal point, and "." (period) as thousands separator. Leaving the ";" (semicolon) to act as the field delimiter.
I couldn’t find any mention in the AB doc you linked to, relating to “thousands separator”.
If the suggestions from @chris25 and @beppe don't suit/ work for you, could you go back to the source of the data, and specify export in US format, which is what AB is mainly geared-for.
Another alternative, if it’s a once-off import, create a brand new spreadsheet, paste the data, and convert it to columns using the “;” as delimiter in the text-to-columns wizard. This is what I get in Excel 365, before doing a global search/replace on “,”:
Ticker Date Time Open Max Min Close Volume Qtd
VALE3 21/12/2018 17:10:00 50,94 50,98 50,80 50,94 8.711.232,00 171.2
VALE3 21/12/2018 17:00:00 51,07 51,12 50,94 50,97 13.022.520,00 255.1
VALE3 21/12/2018 16:40:00 51,05 51,14 51,00 51,02 18.582.686,00 363.9
VALE3 21/12/2018 16:30:00 50,79 51,07 50,72 51,02 19.875.435,00 390.3
VALE3 21/12/2018 16:20:00 50,51 50,90 50,50 50,77 113.447.936,00 2.238.300
You might also need to look at the default thousands separator for your spreadsheet, and possibly even Windows, which may be having an effect on the formatting of the data you receive. In Excel, “File, Options, Advanced”.