!package inputenc error unicode character ​(u+200a)

im currently writing my bachelors thesis and while inserting some cites and adding something to my bib file the above mentioned error occured. i tried to "fix" it by removing all the steps prior to the occuring error but it still remains and i just cant find any solution. since im a total newbie in latex, i would be grateful for any quick help! i found something that should remove this error but it doesnt:

\DeclareUnicodeCharacter{200}{„ “}


which i insert directly after

 \usepackage[utf8]{inputenc}


but that still doesnt solve it

• the error is about character U+200a (HAIR SPACE) but you have defined character U+0200 (LATIN CAPITAL LETTER A WITH DOUBLE GRAVE) – David Carlisle Mar 25 '19 at 20:11
• Are you sure you want a literal Hair space character in your sources? Rather than define the character it is probably better to delete it. – David Carlisle Mar 25 '19 at 20:12
• i have deleted everything i added and its still there. how could i define the hair space? (and what is it anyway?) – Stammer91 Mar 25 '19 at 20:14
• it is a thin space character, add \DeclareUnicodeCharacter{200A}{!!!FIX ME!!!} to your preamble and then see where that text appears and retype that part of the source without the thin space character – David Carlisle Mar 25 '19 at 20:17
• If the text doesn't appear delete the definition and pretend it never happened:-) (it may have been in an auxiliary file and an earlier edit removed it after sufficient latex runs to regenerate everything) – David Carlisle Mar 25 '19 at 20:27

it is a thin space character, add

\DeclareUnicodeCharacter{200A}{!!!FIX ME!!!}


to your preamble and then see where that text appears and retype that part of the source without the thin space character

The log file should also pinpoint the error, it will look something like

(./somefile
<other messages>
! Package inputenc Error: Unicode character Δ (U+0394)
(inputenc)                not set up for use with LaTeX.

See the inputenc package documentation for explanation.
Type  H <return>  for immediate help.
...

l.766 \item \textbf{Distance $Δ$}
- how much did we move by?
You may provide a definition with
\DeclareUnicodeCharacter


which tells you that the character is on line 766 of somefile.tex

• thx it helped solve the error, the thing is, that !!!FIX ME!!! doesnt appear anywhere – Stammer91 Mar 25 '19 at 20:29
• @Stammer91 and does the error re-appear if you delete the definition? – David Carlisle Mar 25 '19 at 20:31
• strangely it doesnt. i just dont understand latex – Stammer91 Mar 25 '19 at 20:51
• @Stammer91 if you provided a small test file, it would be easy to debug, if you don't, it isn't, but you have that character somewhere in your sources so an alternative is to use grep or perl or python etc and just search for the character. – David Carlisle Mar 25 '19 at 20:58
• You don't really need that (we have that, or at least hopefully we do: I wrote the code that's generating that error message:-) But you have the example, all you need to do is delete any text that you can delete while still showing the error and then post the resulting smallest file that has the error, if you half the file size at each iteration it should only take a few iterations to get down to a 1-page example. @Stammer91 – David Carlisle Mar 25 '19 at 21:02