MacOS – How to tell open file dialogs to hide invalid file types

Once you find the file using Alfred, you can copy its path to the clipboard and paste that path into the Go to Folder tool of open/save dialogs.

Find your file in Alfred, press the right arrow key to view the list of operations for that file, the up arrow key to go to the last option (Copy path to clipboard), and then the enter key to activate that option.
Switch back to the open/save dialog, press cmd-shift-g to open the Go to Folder dialog, paste the path in, and hit enter. The file will be selected and you can hit Enter to open/save.

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The answer is covered in this microsoft forum discussion, but in essence what you need to do is

• switch to list view in the file dialog
• be sure "Kind" is one of the columns shown
  • if it isn't, hold "control" and click on the bar with column names
  • select "Kind" to show that row
• then you can click on the "Kind" header to sort, and all folders will be together.

This doesn't put folders at the top though. If you really want to do that, you can read the solution someone devised there. The labelled every folder, then sort in list view not by kind, but by label.