diff --git a/document-generator/document-template/build_lib.sh b/document-generator/document-template/build_lib.sh
index 11f82af..64376b7 100755
--- a/document-generator/document-template/build_lib.sh
+++ b/document-generator/document-template/build_lib.sh
@@ -119,6 +119,9 @@ cp $ROOT root.tex
 cp $ISABELLE_HOME_USER/DOF/latex/*.sty .
 cp $ISABELLE_HOME_USER/DOF/latex/*.sty .
 
+# delete outdated aux files from previous runs
+rm -f *.aux 
+
 $ISABELLE_TOOL latex -o sty "root.tex" && \
 $ISABELLE_TOOL latex -o "$OUTFORMAT" "root.tex" && \
 { [ ! -f "$ROOT_NAME.bib" ] || $ISABELLE_TOOL latex -o bbl "root.tex"; } && \