I am new to LaTeX and have compiled my thesis two sided, having previously done it one sided. The Appendix was compiling fine but now the word 'Appendices' appears on an extra page at the end of the last chapter (image attached), then the Appendices start as normal.
I did a test compile (code below) and when I \include a separate document as the appendix, the problem occurs. If I put the text from the appendix in the code below (replacing where it says '\include Testapp\testapp', it doesn't add the page and word. But my appendices are quite long and I would prefer to keep them separate and \include them like I do the separate chapters.
Here is the main code:
\documentclass[12pt,twoside]{book} %,PageStyleII,times,numbering,print,custombib
\usepackage{geometry} % See geometry.pdf to learn the layout options. There are lots.
\geometry{a4paper} % ... or a4paper or a5paper or ...
\usepackage{floatrow}
\usepackage{setspace}
\usepackage{caption}
\usepackage{subcaption}
\usepackage{graphicx}
\usepackage{lscape}
%\usepackage{float}
\usepackage{booktabs}
\captionsetup[figure]{font={small}, skip=1pt, singlelinecheck=false}
\captionsetup[subfigure]{font={small}, skip=1pt, singlelinecheck=false}
\captionsetup{labelfont=bf}
\captionsetup[table]{font={small}, skip=1pt, singlelinecheck=false}
\raggedbottom
\usepackage{lineno}
\usepackage{mathtools}
\usepackage[all]{nowidow}
\usepackage{tocloft}
\usepackage{xpatch}
\usepackage{enumitem}
%\usepackage{amssymb}
\usepackage{cite}
\usepackage{natbib}
\renewcommand\bibname{References}
\usepackage[nottoc]{tocbibind}
\usepackage{appendix}
\usepackage{chngcntr}
\usepackage{longtable}
\usepackage{color, colortbl}
\definecolor{lightgray}{gray}{0.9}
\floatsetup[table]{capposition=top}
\usepackage{makecell}
\begin{document}
% ******************************** Main Matter *********************************
\mainmatter
\chapter{Assessing the evidence for microenvironments in craters}
\label{chap:micro}
\chaptermark{Microenvironments in craters}
Blah blah blah
%********************************** %5th Section **************************************
\begin{appendices} % Using appendices environment for more functunality
\include{Testapp/testapp}
\end{appendices}
\end{document}
The Testapp code is just a document that says:
\appendix{Appendices}
\appendixpage
\addappheadtotoc
\section{Testapp here}
Blah blah blah
Is this something that happens with the Appendix package and can it be fixed? Thanks

\appendixdoes not have an argument. And because you are using theappendixpackage and already\appendixpage, you should either remove\appendix{Appendices}and\appendixpage(see the documentation ofappendicesenvironment and its options in section 2 of the manual of packageappendix) or use it without argument and remove theappendicesenvironment (see the first example at section 2 of the manual of packageappendix). – cabohah Sep 15 '23 at 11:22