diff --git a/doc/contributions.txt b/doc/contributions.txt
index d14e97644fd6cd525407241b0134c21435d7c673..fb9ba82e57d64ba1d28236b71cbfce96ec14530b 100644
--- a/doc/contributions.txt
+++ b/doc/contributions.txt
@@ -13,6 +13,8 @@ Aimee Trescothick
 	VWR-4803
 Alejandro Rosenthal
 	VWR-1184
+Aleric Inglewood
+	SNOW-626
 Alissa Sabre
 	VWR-81
 	VWR-83
diff --git a/indra/newview/llcommandlineparser.cpp b/indra/newview/llcommandlineparser.cpp
index 2f99ca1247d2f34818767d576132beb422ee38ee..c7359a8865f9f0c89258b7fb259a1013cd1bb22f 100644
--- a/indra/newview/llcommandlineparser.cpp
+++ b/indra/newview/llcommandlineparser.cpp
@@ -267,7 +267,11 @@ bool parseAndStoreResults(po::command_line_parser& clp)
     {
         clp.options(gOptionsDesc);
         clp.positional(gPositionalOptions);
-        clp.style(po::command_line_style::default_style 
+		// SNOW-626: Boost 1.42 erroneously added allow_guessing to the default style
+		// (see http://groups.google.com/group/boost-list/browse_thread/thread/545d7bf98ff9bb16?fwc=2&pli=1)
+		// Remove allow_guessing from the default style, because that is not allowed
+		// when we have options that are a prefix of other options (aka, --help and --helperuri).
+        clp.style((po::command_line_style::default_style & ~po::command_line_style::allow_guessing)
                   | po::command_line_style::allow_long_disguise);
         po::basic_parsed_options<char> opts = clp.run();
         po::store(opts, gVariableMap);