+@node Common errors
+@subsection Common errors
+
+The error conditions described below occur often, yet the cause
+is not obvious or easily found. Once seen and understood, they
+are easily handled.
+
+
+@menu
+* Music runs off the page::
+* Apparent error in ../ly/init.ly::
+* Error message Unbound variable %::
+@end menu
+
+@node Music runs off the page
+@unnumberedsubsubsec Music runs off the page
+
+Music running off the page over the right margin or appearing
+unduly compressed is almost always due to entering an incorrect
+duration on a note, causing the final note in a measure to extend
+over the bar line. It is not invalid if the final note in a
+measure does not end on the automatically entered bar line, as the
+note is simply assumed to carry over into the next measure. But
+if a long sequence of such carry-over measures occurs the music
+can appear compressed or may flow off the page because automatic
+line breaks can be inserted only at the end of complete measures,
+i.e., where all notes end before or at the end of the measure.
+
+@warning{An incorrect duration can cause line breaks to be
+inhibited, leading to a line of highly compressed music or
+music which flows off the page.}
+
+The incorrect duration can be found easily if bar checks are used,
+see @ruser{Bar and bar number checks}.
+
+If you actually intend to have a series of such carry-over measures
+you will need to insert an invisible bar line where you want the
+line to break. For details, see @ruser{Bar lines}.
+
+@node Apparent error in ../ly/init.ly
+@unnumberedsubsubsec Apparent error in @code{../ly/init.ly}
+
+Various obscure error messages may appear about syntax errors in
+@code{../ly/init.ly} if the input file is not correctly formed,
+for example, if it does not contain correctly
+matched braces or quote signs.
+
+The most common error is a missing brace, (@code{@}}), at the end of
+a @code{score} block. Here the solution is obvious: check the
+@code{score} block is correctly terminated. The correct structure
+of an input file is described in @ref{How LilyPond input files work}.
+Using an editor which automatically highlights matching brackets and
+braces is helpful to avoid such errors.
+
+This error message can also appear if a terminating quote sign,
+(@code{"}), is omitted. In this case an accompanying error message
+should give a line number close to the line in error. The
+mismatched quote will usually be on the line one or two above.
+
+@node Error message Unbound variable %
+@unnumberedsubsubsec Error message Unbound variable %
+
+This error message will appear at the bottom of the console
+output or log file together with a @qq{GUILE signalled an error ...}
+message every time a Scheme routine is called which (invalidly)
+contains a @emph{LilyPond} rather than a @emph{Scheme} comment.
+
+LilyPond comments begin with a percent sign, (@code{%}), and must
+not be used within Scheme routines. Scheme comments begin with a
+semi-colon, (@code{;}).