diff --git a/Code/Mantid/Framework/Kernel/src/MultiFileNameParser.cpp b/Code/Mantid/Framework/Kernel/src/MultiFileNameParser.cpp
index 5fe1b3043bcbd94631cdf39e6933b2a7cb177269..8d56ccf05a4d5c7e9314e7b9dab6615412cdb95a 100644
--- a/Code/Mantid/Framework/Kernel/src/MultiFileNameParser.cpp
+++ b/Code/Mantid/Framework/Kernel/src/MultiFileNameParser.cpp
@@ -261,12 +261,33 @@ namespace Kernel
       std::string base = m_multiFileName.substr(
         m_dirString.size(), m_multiFileName.size() - (m_dirString.size() + m_extString.size()));
 
-      // Get the instrument name using a regex.  Throw if not found since this is required.
+      // Get the instrument name using a regex.
       m_instString = getMatchingString("^" + Regexs::INST, base);
+
       if(m_instString.empty())
-        throw std::runtime_error("There does not appear to be an instrument name present.");
+      {
+        // Use default instrument name if one is not found.
+        m_instString = ConfigService::Instance().getString("default.instrument");
 
-      // Check if instrument exists, if not then clear the parser, and rethrow an exception.
+        // The run string is now what's left.  Throw if nothing found since runs are required.
+        m_runString = base;
+        if(m_runString.empty())
+          throw std::runtime_error("There does not appear to be any runs present.");
+      }
+      else
+      {
+        // Check for an underscore after the instrument name.
+        size_t underscore = base.find_first_of("_");
+        if(underscore == m_instString.size())
+          m_underscoreString = "_";
+
+        // We can now deduce the run string.  Throw if not found since this runs are required.
+        m_runString = base.substr(m_underscoreString.size() + m_instString.size());
+        if(m_instString.empty())
+          throw std::runtime_error("There does not appear to be any runs present.");
+      }
+      
+      // Get zero padding of instrument. If throws then instrument does not exist.
       try
       {
         InstrumentInfo instInfo = ConfigService::Instance().getInstrument(m_instString);
@@ -276,16 +297,6 @@ namespace Kernel
       {
         throw std::runtime_error("There does not appear to be a valid instrument name present.");
       }
-
-      // Check for an underscore after the instrument name.
-      size_t underscore = base.find_first_of("_");
-      if(underscore == m_instString.size())
-        m_underscoreString = "_";
-
-      // We can now deduce the run string.  Throw if not found since this is required.
-      m_runString = base.substr(m_underscoreString.size() + m_instString.size());
-      if(m_instString.empty())
-        throw std::runtime_error("There does not appear to be any runs present.");
     }
 
     /////////////////////////////////////////////////////////////////////////////
diff --git a/Code/Mantid/Framework/Kernel/test/MultiFileNameParserTest.h b/Code/Mantid/Framework/Kernel/test/MultiFileNameParserTest.h
index 5e6ec38ab1407704cb767ea885b43eab114ade9e..eafaf3a479b0ff3aa93c461a9567b180a72ca7fd 100644
--- a/Code/Mantid/Framework/Kernel/test/MultiFileNameParserTest.h
+++ b/Code/Mantid/Framework/Kernel/test/MultiFileNameParserTest.h
@@ -4,6 +4,7 @@
 #include <cxxtest/TestSuite.h>
 
 #include "MantidKernel/MultiFileNameParser.h"
+#include "MantidKernel/ConfigService.h"
 
 #include <vector>
 
@@ -302,14 +303,25 @@ public:
       "No file name to parse.");
   }
 
-  void test_errorThrownIfPassedNoInstrumentName()
+  void test_defaultInstrumentUsedIfPassedNoInstrumentName()
   {
     Parser parser;
+    
+    Mantid::Kernel::ConfigService::Instance().setString("default.instrument", "TSC");
 
-    TS_ASSERT_THROWS_EQUALS(parser.parse("c:/20:30.raw"),
-      const std::runtime_error & re, 
-      std::string(re.what()),
-      "There does not appear to be an instrument name present.");
+    parser.parse("c:/2:4.raw");
+
+    TS_ASSERT_EQUALS(parser.dirString(), "c:/");
+    TS_ASSERT_EQUALS(parser.instString(), "TSC");
+    TS_ASSERT_EQUALS(parser.underscoreString(), "");
+    TS_ASSERT_EQUALS(parser.runString(), "2:4");
+    TS_ASSERT_EQUALS(parser.extString(), ".raw");
+
+    std::vector<std::vector<std::string> > filenames = parser.fileNames();
+
+    TS_ASSERT_EQUALS(filenames[0][0], "c:/TSC00002.raw");
+    TS_ASSERT_EQUALS(filenames[1][0], "c:/TSC00003.raw");
+    TS_ASSERT_EQUALS(filenames[2][0], "c:/TSC00004.raw");
   }
 };