# Biber & Biblatex - getting errors when more than one citation

I am using Texstudio 2.6.4, Miktex 2.9, Biber 1.8 and Biblatex 2.9 on Win7x64. I switched from Natbib to Biblatex as I want to use some of the better citation options in my thesis. I kept getting error messages and have read through all entries that are out there without finding a solution to this problem: Whenever there is more than 1 citation I get an error message. See the following MWE:

\documentclass[onecolumn,a4paper,12pt, oneside, openright]{report}
\usepackage[english]{babel}
\usepackage{csquotes}
\usepackage[natbib=true, style=authoryear, hyperref=true, backend=biber]{biblatex}
\begin{document}

\input{chapter1}

\printbibliography

\end{document}

Whith Chapter 1 looking like this:

\onehalfspace
\chapter[Introduction]{Introduction}
\chaptermark{Introduction}

\section{Section1}

Text \autocite{test1}. Text \autocite{test2}.

When I compile using pdflatex biber pdflatex pdflatex I get the following error message from Biber:

Process started: "C:/Program Files (x86)/MiKTeX 2.9/miktex/bin/biber.exe" "Thesis"

INFO - This is Biber 1.8
INFO - Logfile is 'Thesis.blg'
WARN - Warning: Found biblatex control file version 2.6, expected version 2.5
INFO - Found 3 citekeys in bib section 0
INFO - Processing section 0
INFO - Looking for bibtex format file 'M:/PhD/Documents/Latex/Thesis/Export2.bib' for section 0
INFO - Found BibTeX data source 'M:/PhD/Documents/Latex/Thesis/Export2.bib'

Process exited with error(s)

And the citations in the document look like the code (test1, test2) and no bibliography has been created. I assume it has to do with the line:

WARN - Warning: Found biblatex control file version 2.6, expected version 2.5

Yet this line does not make sense as I use biblatex version 2.9. In addition, if I delete the second citation there is the same warning message but it compiles just fine:

INFO - This is Biber 1.8
INFO - Logfile is 'Thesis.blg'
WARN - Warning: Found biblatex control file version 2.6, expected version 2.5
INFO - Found 2 citekeys in bib section 0
INFO - Processing section 0
INFO - Looking for bibtex format file 'M:/PhD/Documents/Latex/Thesis/Export2.bib' for  section 0
INFO - Found BibTeX data source 'M:/PhD/Documents/Latex/Thesis/Export2.bib'
INFO - Overriding locale 'English_United States.1252' default tailoring 'variable = shifted' with 'variable = non-ignorable'
INFO - Sorting 'entry' list 'nyt' keys
INFO - No sort tailoring available for locale 'English_United States.1252'
INFO - Writing 'Thesis.bbl' with encoding 'ascii'
INFO - Output to Thesis.bbl
INFO - WARNINGS: 1

Process exited normally

The citation is correct and a bibliography has been created. So maybe that warning message is not right? Any help would be greatly appreciated!

-
The warning does indeed make sense (the biblatex control file (bcf) versions are not the same as the biblatex versions; version 2.5 for bcf corresponds to version 2.8 in biblatex, 2.6 to 2.9). Your version of biblatex and Biber do not match: biblatex v 2.8 requires Biber 1.8, while version 2.9 of biblatex needs Biber 1.9. So either update Biber to 1.9 or downgrade biblatex to 2.8. –  moewe Feb 7 at 15:04
Also strange: Biber says it found 3 or 2 citekeys, but you used 2 or 1. Could you try and put everything into one single MWE that is directly compilable? And please check the versions again, biblatex 2.9 is not yet released. –  matth Feb 7 at 17:50

Here is a MWE that you can use as test case, it does compile fine on my computer.

\documentclass[]{article}
\listfiles % will put version info to .log file
\usepackage[autostyle]{csquotes}
\usepackage[backend=biber]{biblatex}