Since it was working before Mountain Lion, with, presumably, similar file sizes and numbers of items, I'm thinking the advantage of text item delimiters is that now you can use a list of items as delimiters, which could work better than doing the repeat loop and the "contains" test. Unless there is some reason why a doing this on a list with thousands of items would have worked before mountain lion but not work with mountain lion. Do we know of a mountain lion specific issue? ES >> set thePieces to splittext bigFile using "whatever" > > Are you doing a literal split or a regex split with the splittext command? if > the former, why not use text item delimiters instead? If the latter, there was > a problem with it reported over on macscripter.net recently. > > But perhaps the more important question is how many items thePieces contains. > If it's many thousands, you're going to want to break the job into smaller > parts.