Unpivot data in Power Query based on Date range

Hi,

Try this formula

let
Source = Excel.CurrentWorkbook(){[Name="Table3"]}[Content],
#"Changed Type" = Table.TransformColumnTypes(Source,{{"Start Date", type date}, {"End Date", type date}}),
#"Merged Columns" = Table.CombineColumns(#"Changed Type",{"Start Date", "End Date"},each (if _{1}=null then _{0} else List.Dates(_{0},Duration.Days(_{1}-_{0}),#duration(1, 0, 0, 0))),"Date"),
#"Expanded Date" = Table.ExpandListColumn(#"Merged Columns", "Date")
in
#"Expanded Date"

Anonymous, add a Custom Column with this formula and let me know if there is any problem:

List.Dates([Start date], Duration.Days([End date] - [Start date]) + 1, #duration(1, 0, 0, 0))

Expand the new column to generate rows for each date.
Remove the original "Start date" and "End date" columns if not needed.