[texworks] Error with every LaTex-Distribution (ifpdftex already defined)

baluyellow at web.de baluyellow at web.de
Wed Apr 8 23:48:02 CEST 2020

Hello guys,

I am not certain how to write this mail, but I will try my best. I have a recurring error. I tried uninstalling and installing my distribution (first MikTeX, then TeXLive). The error reads as follows : "

! LaTeX Error: Command \ifpdftex already defined.

Or name \end... illegal, see p.192 of the manual. "

The problem seems to be in the pdfcprot-package. In MikTeX as well as TeXLive I was not able to remove the package since its essential. I tried the  " \let\ifpdftex\relax" solution I found on the internet but no results so far. I am farily new to the subject so I might be missing a point. I really dont understand how its possible to have a package double defined after uninstalling everything and even changing the source of the package. Here is my preamble:







captions=tableheading, %Überschrift über Tabelle (nicht unter)



%\usepackage[style=chem-acs]{biblatex} %Falls Referenzen mitthilfe von biblatex angelegt werden wollen





\sisetup{exponent-product = \cdot, output-product = \cdot, separate-uncertainty=true}



\usepackage{graphicx} %Bilder einbinden












% recommended:























I would really appreciate an answer. Thanks!

Best Regards,

Noah Spitzner

----- configuration info -----
TeXworks version : 0.6.3r.a2470ca (travis-ci)
Install location : C:/texlive/2019/tlpkg/texworks/texworks.exe
Library path : C:/Users/Manager/.texlive2019/texmf-config/texworks\
pdfTeX location : C:/texlive/2019/bin/win32/pdftex.exe
Operating system : Windows 10, 64-bit
Qt version : 5.12.1 (build) / 5.12.1 (runtime)

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