These are just preferences - it will still always mark all but one file in each group. Try 'All but one matching set'
See manual note:
These are preferences only - If you are marking 'all but one in each group' and preferring files with 'Copy' in the name and there aren't any files with 'Copy' in that group, all but one will still be marked. In this case, for stricter requirements, 'All but one matching set' may be the way to go. https://www.digitalvolcano.co.uk/duplic ... =&sct=MA==
Okay, thanks. Probably it is not possible to select duplicate files base on extension?
Assumed that 'File type' referred to extension.
Anyway, I solved this 'manually'.
Thanks again.
You can by marking all the files that have the extension you want to remove, then filter by group having marked files and then using the filter you have shown above. However notice that it a priority filter, which means as shown above it will mark all the files except the ones with the shortest filenames and only if the length is the same it will prefer the ones starting with the type mentioned. So I think what you want to do is to switch the priorities so that all the files with the type will be prioritised and only of they both start with what you wrote it will keep the one with the shortest name (selecting the longest)