Somehow that action does not make any difference: upper case stays upper case, mixed case stays mixed case .. Do I really have to type in the new filename and the extension and then run the action? Wouldn't it then be much easier to do that in the file explorer which saves me the effort to create fields, write them, start the action and then delete them?
And even though you claim to have a
way - it is not: if I enter e.g. mP3 as new file extension, the extension becomes lower case.
Why doesn't the action create the fields it needs when all it does is to convert to lower case only any way?
Where is the benefit that I have to create user-definded fields first, then apply the action, then delete these fields again?
While a simple "Replace with regular expression" would serve the same purpose much quicker, see
It could still be that I have simply not grasped what this should be all about.