Remove all rows with same value in collumn

Take a look at what this code is doing. Paste it in a blank query. It removes all non-unique records.

1) In Power Query, select New Source, then Blank Query
2) On the Home ribbon, select "Advanced Editor" button
3) Remove everything you see, then paste the M code I've given you in that box.
4) Press Done

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WSlSK1YlWSgKTyWAyBUymgsk0MJkOJhORyCQklUAyFgA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type text) meta [Serialized.Text = true]) in type table [Column1 = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Column1", type text}}),
    #"Grouped Rows" = Table.Group(#"Changed Type", {"Column1"}, {{"Count", each Table.RowCount(_), type number}, {"All Rows", each _, type table [Column1=text]}}),
    #"Filtered Rows" = Table.SelectRows(#"Grouped Rows", each ([Count] = 1)),
    #"Expanded All Rows" = Table.ExpandTableColumn(#"Filtered Rows", "All Rows", {"Column1"}, {"Column1.1"})
in
    #"Expanded All Rows"