diff --git a/doc/html/Section_errors.html b/doc/html/Section_errors.html
index 658dfb8c2d..a8fd33e6b7 100644
--- a/doc/html/Section_errors.html
+++ b/doc/html/Section_errors.html
@@ -486,8 +486,7 @@ be computed.</dd>
 <dt><em>Bad TIP4P bond type for PPPMDisp/TIP4P</em></dt>
 <dd>Specified bond type is not valid.</dd>
 <dt><em>Bad fix ID in fix append/atoms command</em></dt>
-<dd>The value of the fix_id for keyword spatial must start with the suffix
-<a href="#id6"><span class="problematic" id="id7">f_</span></a>.</dd>
+<dd>The value of the fix_id for keyword spatial must start with &#8216;<a href="#id6"><span class="problematic" id="id7">f_</span></a>&#8216;.</dd>
 <dt><em>Bad grid of processors</em></dt>
 <dd>The 3d grid of processors defined by the processors command does not
 match the number of processors LAMMPS is being run on.</dd>
diff --git a/doc/src/Section_errors.txt b/doc/src/Section_errors.txt
index 52405f684b..7f5f7857a5 100644
--- a/doc/src/Section_errors.txt
+++ b/doc/src/Section_errors.txt
@@ -535,8 +535,7 @@ Specified bond type is not valid. :dd
 
 {Bad fix ID in fix append/atoms command} :dt
 
-The value of the fix_id for keyword spatial must start with the suffix
-f_. :dd
+The value of the fix_id for keyword spatial must start with 'f_'. :dd
 
 {Bad grid of processors} :dt