! Package inputenc Error: Unicode char ́ (U+301)(inputenc)

I do this:

\DeclareUnicodeCharacter{0301}{*************************************}

and look into the pdf which char produces this and delete/correct it.

If you copy/paste some source, it may happen that é had been coded as

U+0065 U+0301

which in Unicode aware environments is rendered as expected. Unfortunately pdflatex is not Unicode aware and cannot deal with combining characters, which are placed after the character they refer to.

The only method that gives correct results is to change the combination into the non composed character.

Doing \DeclareUnicodeCharacter{0301}{\'{e}} is wrong. Here's an example:

\documentclass{article}

\DeclareUnicodeCharacter{0301}{\'{e}}

\begin{document}

é % non composed character U+00E9
é % composed character U+0065 U+0301
ú % composed character U+0075 U+0301

\end{document}

You're removing the error message, but the output is completely off.

_{Note Copying from the above will not show the precomposed characters, because either my OS or this site does normalization.}