diff --git a/fontexist.m b/fontexist.m
index e6647eb..94b8029 100644
--- a/fontexist.m
+++ b/fontexist.m
@@ -5,9 +5,9 @@
 % Created 2016-01-05 by Jorg C. Woehl
 % 2016-12-16 (JCW): Converted to standalone function, comments added.
 
-% input: empty character array, or nonempty character vector
+% input: empty character array, or character vector
 assert(ischar(font) && (isrow(font) || isempty(font)),...
-    'fontexist:IncorrectInputType', 'Input must be an empty character array or a nonempty character vector.');
+    'fontexist:IncorrectInputType', 'Input must be an empty character array or a character vector.');
 if isempty(font)
     % reduce to simplest empty type
     font = '';
@@ -16,4 +16,4 @@
 idx = find(strcmpi(listfonts, font), 1);
 bool = ~isempty(idx);
 
-end
\ No newline at end of file
+end
diff --git a/getOSfont.m b/getOSfont.m
index 2d1d43d..303eb51 100644
--- a/getOSfont.m
+++ b/getOSfont.m
@@ -46,20 +46,20 @@
 
 %% Input argument validation
 
-% input 1: empty character array, or nonempty character vector
+% input 1: empty character array, or character vector
 assert(ischar(OS) && (isrow(OS) || isempty(OS)), 'getOSfont:IncorrectInputType',...
-    'Input 1 must be an empty character array or a nonempty character vector.');
+    'Input 1 must be an empty character array or a character vector.');
 % convert to all lowercase if necessary
 OS = lower(OS);
 if isempty(OS)
     % reduce to simplest empty type
     OS = '';
 else
-    % input 2: (nonempty) numeric vector containing finite real non-negative "integers"
-    assert(isnumeric(OSVersion) && isvector(OSVersion) && all(isfinite(OSVersion))...
+    % input 2: nonempty numeric vector containing finite real non-negative "integers"
+    assert(isnumeric(OSVersion) && ~isempty(OSVersion) && isvector(OSVersion) && all(isfinite(OSVersion))...
         && isreal(OSVersion) && all(OSVersion == round(OSVersion)) && all(OSVersion >= 0),...
         'getOSfont:IncorrectInputType',...
-        'Input 2 must be a (nonempty) vector containing finite real non-negative integer values (of any numeric type).');
+        'Input 2 must be a nonempty vector containing finite real non-negative integer values (of any numeric type).');
 end
 
 %% Determine system UI font
@@ -161,4 +161,4 @@
     OSFont = '';
 end
 
-end
\ No newline at end of file
+end