This question might have a really simple answer that I don't see or it might be multiple stuff that I miss cause of my limited experience in TeX.
I am writing my thesis (my first and quite large project). My setup is MacTex '14 + Texmaker + subfiles package.
After quite a lot of effort this ecosystem used to work perfectly, but now that I wanted to add bibliography (package + addbibresouce+ printbibliography commands) the compilation fails with weird errors like the ones in the attached screenshot. Once I comment those lines, the first compilation fails again and after the second compilation and then, everything is back to normal.
Same thing happens when I try to add an appendix, with a slight difference that the first time after I add the \appendix command, pdf is produced. After one more compilation, chaos.
My build in Texmaker is Xelatex+ View pdf
%--------------------------------- Preamble for XelaTeX---------------------------------
\documentclass{report}
% Main Packages
%\usepackage[utf8]{inputenc}
\usepackage{fontspec}
\usepackage{subfiles}
%Bibliography
%\usepackage[backend=biber]{biblatex}
\usepackage{biblatex}
\addbibresource{bibliography.bib}
\usepackage{polyglossia}
\setmainlanguage{greek}
\setotherlanguage{english}
%--------------------------------- Main Document----------------------------
\begin{document}
\chapter{foo}
\subfile{chapters/ch1}
\chapter{foo1}
\subfile{chapters/ch2}
\chapter{foo2}
\subfile{chapters/ch3}
\printbibliography
%\appendix
\end{document}

.aux&.bbl. – moewe Sep 13 '15 at 13:20biblatexexpects the other format, then after a run of the bibliography backend the temporary files are back to whatbiblatexexpects. – moewe Sep 13 '15 at 13:22biblatexthe lines\usepackage[backend=biber]{biblatex}and\usepackage{biblatex}should be equivalent, but the former is preferred. Which version does MacTex 2014 ship with? – moewe Sep 13 '15 at 13:25\usepackage[backend=biber]{biblatex}you need to run Biber. (If you use\usepackage[backend=bibtex]{biblatex}you need BibTeX). It is better to specify the backend at loading time, so we don't get confused. You can see the link above for a integration of Biber into your editor. – moewe Sep 13 '15 at 14:13babelthe order does not seem to matter greatly. Since you solved your problem, why don't you write up a short answer yourself? – moewe Sep 13 '15 at 15:29