Hi @SSibbett
This works no problem here assuming the number of closing parentheses is OK:
let
Source = Folder.Files("C:\File\Path\Location"),
#"Filtered Rows" = Table.SelectRows(Source, each ([Extension] = ".xlsx") and (Text.Contains([Name],"Data")))
in
#"Filtered Rows"
Could you confirm and if this solves your problem please mark this reply as answer to help others with a similar issue - Thanks