I am still converting my pdflatex codes to XeLaTeX.
Minimal case
\documentclass{article}
% The Question -environment works with these two lines
% \usepackage{amsfonts, amssymb, textcomp, mathtools, xparse}
% \usepackage[T4, OT1]{fontenc}
% http://tex.stackexchange.com/q/213457/13173
\usepackage{mathtools, xparse} % load mathtools before loading fontspec
% amsmath never needed with mathtools
\usepackage{amsfonts, amssymb, textcomp} % not sure if these are necessary
% http://tex.stackexchange.com/a/213430/13173
\usepackage{polyglossia} % also loads package fontspec
\setmainfont{Minion Pro} % or whatever OTF you have on your system
\setmainlanguage{english} % loads language hyphenation rules and such
\usepackage{unicode-math} % if you also need maths
\setmathfont{Cambria Math} % or whatever math OTF you have on your system
\usepackage[framemethod=tikz]{mdframed}
% Problem here
% This environment do not work with the above packages
\mdfdefinestyle{ans}{
linecolor=cyan,
backgroundcolor=yellow!20,
frametitlebackgroundcolor=green!40,
frametitlerule=true
}
\newcounter{question}[section]%
\setcounter{question}{0}
\newenvironment{question}[1]{%
\refstepcounter{question}%
\begin{mdframed}[style=ans,frametitle={Question: #1}]
}{%
\end{mdframed}%
}%
\begin{document}
\begin{question}
{Is this Lorem Ipsun?}
Yes, it is.
\end{question}
\end{document}
where the mdframed -package seems to designed with pdflatex, since it works with the two lines (7) and (8).
The strange errors

suggests me that the new packages do not understand the syntax which I have used with Question -environment.
Errors and warnings are like this
*************************************************
* unicode-math warning: "mathtools-overbracket"
*
* Using \overbracket and \underbracke from `mathtools' package.
*
* Use \Uoverbracket and \Uunderbracke for original `unicode-math' definition.
*************************************************
ABD: EveryShipout initializing macros
./test.tex:41: Too many }'s.
\endmdf@lrbox ->\color@endgroup \egroup
l.41 \end{question}
Package mdframed Warning: The environment is empty
(mdframed) on input line 41.
./test.tex:41: Extra \endgroup.
\color@endgroup ->\endgraf \endgroup
l.41 \end{question}
./test.tex:41: LaTeX Error: \begin{document} ended by \end{mdframed}.
See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...
l.41 \end{question}
./test.tex:41: Extra \endgroup.
<recently read> \endgroup
l.41 \end{question}
./test.tex:41: LaTeX Error: \begin{document} ended by \end{question}.
See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...
l.41 \end{question}
./test.tex:41: Extra \endgroup.
<recently read> \endgroup
l.41 \end{question}
[1] (/Users/masi/Desktop/.texpadtmp/test.aux) )
(see the transcript file for additional information)
Output written on /Users/masi/Desktop/.texpadtmp/test.pdf (1 page).
SyncTeX written on /Users/masi/Desktop/.texpadtmp/test.synctex.gz.
Transcript written on /Users/masi/Desktop/.texpadtmp/test.log.
Output of \listfiles
*File List*
article.cls 2007/10/19 v1.4h Standard LaTeX document class
size10.clo 2007/10/19 v1.4h Standard LaTeX file (size option)
mathtools.sty 2013/02/12 v1.13 mathematical typesetting tools
keyval.sty 1999/03/16 v1.13 key=value parser (DPC)
calc.sty 2007/08/22 v4.3 Infix arithmetic (KKT,FJ)
mhsetup.sty 2010/01/21 v1.2a programming setup (MH)
amsmath.sty 2013/01/14 v2.14 AMS math features
amstext.sty 2000/06/29 v2.01
amsgen.sty 1999/11/30 v2.0
amsbsy.sty 1999/11/29 v1.2d
amsopn.sty 1999/12/14 v2.01 operator names
xparse.sty 2013/12/31 v4634 L3 Experimental document command parser
expl3.sty 2014/01/07 v4646 L3 Experimental code bundle wrapper
l3names.sty 2014/01/04 v4640 L3 Namespace for primitives
l3bootstrap.sty 2014/01/04 v4640 L3 Experimental bootstrap code
etex.sty 1998/03/26 v2.0 eTeX basic definition package (PEB)
l3basics.sty 2014/01/04 v4642 L3 Basic definitions
l3expan.sty 2014/01/04 v4642 L3 Argument expansion
l3tl.sty 2013/12/27 v4625 L3 Token lists
l3seq.sty 2013/12/14 v4623 L3 Sequences and stacks
l3int.sty 2013/08/02 v4583 L3 Integers
l3quark.sty 2013/12/14 v4623 L3 Quarks
l3prg.sty 2014/01/04 v4642 L3 Control structures
l3clist.sty 2013/07/28 v4581 L3 Comma separated lists
l3token.sty 2013/08/25 v4587 L3 Experimental token manipulation
l3prop.sty 2013/12/14 v4623 L3 Property lists
l3msg.sty 2013/07/28 v4581 L3 Messages
l3file.sty 2013/10/13 v4596 L3 File and I/O operations
l3skip.sty 2013/07/28 v4581 L3 Dimensions and skips
l3keys.sty 2013/12/08 v4614 L3 Experimental key-value interfaces
l3fp.sty 2014/01/04 v4642 L3 Floating points
l3box.sty 2013/07/28 v4581 L3 Experimental boxes
l3coffins.sty 2013/12/14 v4624 L3 Coffin code layer
l3color.sty 2012/08/29 v4156 L3 Experimental color support
l3luatex.sty 2013/07/28 v4581 L3 Experimental LuaTeX-specific functions
l3candidates.sty 2014/01/06 v4643 L3 Experimental additions to l3kernel
ifpdf.sty 2011/01/30 v2.3 Provides the ifpdf switch (HO)
amsfonts.sty 2013/01/14 v3.01 Basic AMSFonts support
amssymb.sty 2013/01/14 v3.01 AMS font symbols
textcomp.sty 2005/09/27 v1.99g Standard LaTeX package
ts1enc.def 2001/06/05 v3.0e (jk/car/fm) Standard LaTeX file
polyglossia.sty 2013/06/27 v1.33.4 Babel replacement for XeLaTeX and LuaTeX
etoolbox.sty 2011/01/03 v2.1 e-TeX tools for LaTeX
makecmds.sty 2009/09/03 v1.0a extra command making commands
xkeyval.sty 2012/10/14 v2.6b package option processing (HA)
xkeyval.tex 2012/10/14 v2.6b key=value parser (HA)
fontspec.sty 2013/05/20 v2.3c Font selection for XeLaTeX and LuaLaTeX
fontspec-patches.sty 2013/05/20 v2.3c Font selection for XeLaTeX and LuaLaTe
X
fixltx2e.sty 2006/09/13 v1.1m fixes to LaTeX
fontspec-xetex.sty 2013/05/20 v2.3c Font selection for XeLaTeX and LuaLaTeX
fontenc.sty
eu1enc.def 2010/05/27 v0.1h Experimental Unicode font encodings
eu1lmr.fd 2009/10/30 v1.6 Font defs for Latin Modern
xunicode.sty 2011/09/09 v0.981 provides access to latin accents and many oth
er characters in Unicode lower plane
eu1lmss.fd 2009/10/30 v1.6 Font defs for Latin Modern
graphicx.sty 1999/02/16 v1.0f Enhanced LaTeX Graphics (DPC,SPQR)
graphics.sty 2009/02/05 v1.0o Standard LaTeX Graphics (DPC,SPQR)
trig.sty 1999/03/16 v1.09 sin cos tan (DPC)
graphics.cfg 2010/04/23 v1.9 graphics configuration of TeX Live
xetex.def 2013/04/29 v0.96 LaTeX color/graphics driver for XeTeX (RRM/JK)
fontspec.cfg
ifluatex.sty 2010/03/01 v1.3 Provides the ifluatex switch (HO)
gloss-english.ldf polyglossia: module for english
unicode-math.sty 2013/05/04 v0.7e Unicode maths in XeLaTeX and LuaLaTeX
ifxetex.sty 2010/09/12 v0.6 Provides ifxetex conditional
l3keys2e.sty 2013/12/31 v4634 LaTeX2e option processing using LaTeX3 keys
catchfile.sty 2011/03/01 v1.6 Catch the contents of a file (HO)
infwarerr.sty 2010/04/08 v1.3 Providing info/warning/error messages (HO)
ltxcmds.sty 2011/11/09 v1.22 LaTeX kernel commands for general use (HO)
etexcmds.sty 2011/02/16 v1.5 Avoid name clashes with e-TeX commands (HO)
fix-cm.sty 2006/09/13 v1.1m fixes to LaTeX
ts1enc.def 2001/06/05 v3.0e (jk/car/fm) Standard LaTeX file
filehook.sty 2011/10/12 v0.5d Hooks for input files
unicode-math-xetex.sty
unicode-math-table.tex
mdframed.sty 2013/07/01 1.9b: mdframed
kvoptions.sty 2011/06/30 v3.11 Key value format for package options (HO)
kvsetkeys.sty 2012/04/25 v1.16 Key value parser (HO)
zref-abspage.sty 2012/04/04 v2.24 Module abspage for zref (HO)
zref-base.sty 2012/04/04 v2.24 Module base for zref (HO)
kvdefinekeys.sty 2011/04/07 v1.3 Define keys (HO)
pdftexcmds.sty 2011/11/29 v0.20 Utility functions of pdfTeX for LuaTeX (HO)
auxhook.sty 2011/03/04 v1.3 Hooks for auxiliary files (HO)
atbegshi.sty 2011/10/05 v1.16 At begin shipout hook (HO)
needspace.sty 2010/09/12 v1.3d reserve vertical space
color.sty 1999/02/16
color.cfg 2007/01/18 v1.5 color configuration of teTeX/TeXLive
tikz.sty 2013/12/13 v3.0.0 (rcs-revision 1.142)
pgf.sty 2013/12/18 v3.0.0 (rcs-revision 1.14)
pgfrcs.sty 2013/12/20 v3.0.0 (rcs-revision 1.28)
everyshi.sty 2001/05/15 v3.00 EveryShipout Package (MS)
pgfrcs.code.tex
pgfcore.sty 2010/04/11 v3.0.0 (rcs-revision 1.7)
pgfsys.sty 2013/11/30 v3.0.0 (rcs-revision 1.47)
pgfsys.code.tex
pgfsyssoftpath.code.tex 2013/09/09 (rcs-revision 1.9)
pgfsysprotocol.code.tex 2006/10/16 (rcs-revision 1.4)
xcolor.sty 2007/01/21 v2.11 LaTeX color extensions (UK)
color.cfg 2007/01/18 v1.5 color configuration of teTeX/TeXLive
pgfcore.code.tex
pgfcomp-version-0-65.sty 2007/07/03 v3.0.0 (rcs-revision 1.7)
pgfcomp-version-1-18.sty 2007/07/23 v3.0.0 (rcs-revision 1.1)
pgffor.sty 2013/12/13 v3.0.0 (rcs-revision 1.25)
pgfkeys.sty
pgfkeys.code.tex
pgfmath.sty
pgfmath.code.tex
pgffor.code.tex
tikz.code.tex
md-frame-1.mdf 2013/07/01\ 1.9b: md-frame-1
t3cmr.fd 2001/12/31 TIPA font definitions
***********
)
(see the transcript file for additional information)
Output written on /Users/masi/Desktop/.texpadtmp/test.pdf (1 page).
SyncTeX written on /Users/masi/Desktop/.texpadtmp/test.synctex.gz.
Transcript written on /Users/masi/Desktop/.texpadtmp/test.log.
How can you convert this Question -environment from pdflatex to XeLaTeX in mdframed?
\listfilesto your preamble and post the list that gets printed. – David Carlisle Nov 22 '14 at 22:34