+@node When things don't work
+@section When things don't work
+
+@menu
+* Updating old files::
+* Troubleshooting (taking it all apart)::
+* Minimal examples::
+@end menu
+
+@node Updating old files
+@subsection Updating old files
+
+The LilyPond input syntax occasionally changes. As LilyPond itself
+improves, the syntax (input language) is modified accordingly. Sometimes
+these changes are made to make the input easier to read and write or
+sometimes the changes are made to accomodate new features of LilyPond.
+
+LilyPond comes with a file that makes this updating easier:
+@code{convert-ly}. For details about how to run this program, see
+@rprogram{Updating files with convert-ly}.
+
+Unfortunately, @code{convert-ly} cannot handle all input changes. It
+takes care of simple search-and-replace changes (such as @code{raggedright}
+becoming @code{ragged-right}), but some changes are too
+complicated. The syntax changes that @code{convert-ly} cannot handle
+are listed in @rprogram{Updating files with convert-ly}.
+
+For example, in LilyPond 2.4 and earlier, accents and non-English
+letters were entered using LaTeX -- for example,
+@code{No\"el} (this would print the French word for
+@q{Christmas}). In LilyPond 2.6 and above, the special
+@code{ë} must be entered directly into the LilyPond file as an
+UTF-8 character. @code{convert-ly} cannot change all the LaTeX
+special characters into UTF-8 characters; you must manually update
+your old LilyPond files.
+
+
+@node Troubleshooting (taking it all apart)
+@subsection Troubleshooting (taking it all apart)
+
+Sooner or later, you will write a file that LilyPond cannot
+compile. The messages that LilyPond gives may help
+you find the error, but in many cases you need to do some
+investigation to determine the source of the problem.
+
+The most powerful tools for this purpose are the
+single line comment (indicated by @code{%}) and the block
+comment (indicated by @code{%@{ ... %@}}). If you don't
+know where a problem is, start commenting out huge portions
+of your input file. After you comment out a section, try
+compiling the file again. If it works, then the problem
+must exist in the portion you just commented. If it doesn't
+work, then keep on commenting out material until you have
+something that works.
+
+In an extreme case, you might end up with only
+
+@example
+\score @{
+ <<
+ % \melody
+ % \harmony
+ % \bass
+ >>
+ \layout@{@}
+@}
+@end example
+
+@noindent
+(in other words, a file without any music)
+
+If that happens, don't give up. Uncomment a bit -- say,
+the bass part -- and see if it works. If it doesn't work,
+then comment out all of the bass music (but leave
+@code{\bass} in the @code{\score} uncommented.
+
+@example
+bass = \relative c' @{
+%@{
+ c4 c c c
+ d d d d
+%@}
+@}
+@end example
+
+Now start slowly uncommenting more and more of the
+@code{bass} part until you find the problem line.