diff --git a/gpkit/_mosek/expopt.py b/gpkit/_mosek/expopt.py
index 61fd1dfb1..0111924b2 100644
--- a/gpkit/_mosek/expopt.py
+++ b/gpkit/_mosek/expopt.py
@@ -91,7 +91,7 @@ def c_array(py_array, c_type):
 
 
 MOSEK_VERSION = settings["mosek_version"]
-LIB = path.dirname(path.abspath(__file__)) + sep.join(["build, expopt.so"])
+LIB = path.dirname(path.abspath(__file__)) + sep.join(["build", "expopt.so"])
 MSK = ModuleShortener("MSK", load_library(LIB))
 
 MSK_RES_OK = 0
diff --git a/gpkit/build.py b/gpkit/build.py
index 49d5dd1ea..881a210f9 100644
--- a/gpkit/build.py
+++ b/gpkit/build.py
@@ -212,6 +212,7 @@ def look(self):  # pylint: disable=too-many-return-statements
             if not isfile(expopt_file):
                 return None
         settings["mosek_bin_dir"] = self.bin_dir
+        settings["mosek_version"] = self.version
         os.environ['PATH'] = os.environ['PATH'] + os.pathsep + self.bin_dir
 
         return "version %s, installed to %s" % (self.version, rootdir)
@@ -262,8 +263,6 @@ def build(self):
         if built_expopt_lib != 0:
             return False
 
-        settings["mosek_version"] = self.version
-
         return True