--- a/testing/mozbase/mozinfo/mozinfo/mozinfo.py
+++ b/testing/mozbase/mozinfo/mozinfo/mozinfo.py
@@ -66,16 +66,18 @@ elif system == "Darwin":
     (release, versioninfo, machine) = platform.mac_ver()
     version = "OS X %s" % release
     versionNums = release.split('.')[:2]
     os_version = "%s.%s" % (versionNums[0], versionNums[1])
     info['os'] = 'mac'
 elif sys.platform in ('solaris', 'sunos5'):
     info['os'] = 'unix'
     os_version = version = sys.platform
+else:
+    os_version = version = unknown
 
 info['version'] = version
 info['os_version'] = os_version
 
 # processor type and bits
 if processor in ["i386", "i686"]:
     if bits == "32bit":
         processor = "x86"