diff --git a/SquidAnalyzer.pm b/SquidAnalyzer.pm
index db486c2..dc49830 100644
--- a/SquidAnalyzer.pm
+++ b/SquidAnalyzer.pm
@@ -2939,6 +2939,7 @@ sub parse_user_aliases
 		$i++;
 		next if (!$l || ($l =~ /^[\s\t]*#/)); 
 		my @data = split(/[\t]+/, $l, 2);
+		$data[0] =~ s/\s+/_/g; # Replace space, they are not allowed
 		if ($#data == 1) {
 			push(@{$alias{$data[0]}}, split(/[\s,;\t]/, $data[1]));
 		} else {
diff --git a/user-aliases b/user-aliases
index aa3758f..b6ac34e 100644
--- a/user-aliases
+++ b/user-aliases
@@ -1,7 +1,8 @@
 #-------------------------------------------------------------------------------
 # Squid Analyzer User Alias configuration file
 # FORMAT : FULL_USER_NAME	IP_ADDRESS|LOGIN_NAME,LOGIN_REGEX
-# Field separator must be one or more tabulation. See example bellow
+# Field separator must be one or more tabulation. Space in user name are not
+# allowed. See example bellow
 #-------------------------------------------------------------------------------
 #MyFirstName	mylogin,192.168.1.12
 #MyOtherNames	logon\d+