Total Commander

It's a bad idea to use Bold as error.
Because I can select some font with ExtraBold (e.g. "Jetbrains Mono" + ExtraBold), and TC switch ExtraBold to Bold when error, but difference between ExtraBold and Bold is very small.
Better to use a colored background to highlight errors.

Support+

Support+

As well as a subtle colour for all elements of filenames that are about to change, perhaps a dull yellow-highlight background.
That way, we would be able to tell what characters are changing, not just iterations of the entire new names, as well as those rows that have no changes pending, for whatever reason.
See Bulk-Rename Utility.
But that's for another thread.

Support++