diff --git a/lib/FormulaRepo.py b/lib/FormulaRepo.py
index 4f49ed2..cf9d6a1 100644
--- a/lib/FormulaRepo.py
+++ b/lib/FormulaRepo.py
@@ -1,5 +1,6 @@
 from git import Repo
 import os
+import sys
 
 class FormulaRepo():
 
@@ -30,6 +31,11 @@ class FormulaRepo():
         if tracking_key == 0:
             # tracking a specific branch on the repo
             if tracking_value != False:
+                # check to make sure that the given branch name actually exists first
+                if not tracking_value in self.repo.branches:
+                    print('%s is not an existing branch name for %s - please fix this.' % (tracking_value, self.repo_path))
+                    sys.exit(1)
+
                 repo_branch = self.repo.head.reference
                 # check to make sure that the current tracked branch is, in fact, what we want
                 if repo_branch != tracking_value:
@@ -45,7 +51,9 @@ class FormulaRepo():
             print('Tracking a commit')
         else:
             # we shouldn't get here...
-            print('We shouldn\'t have a tracking key that is not 0, 1 or 2')
+            print('So... somehow %s got a tracking key of %d, but that is not a valid tracking key!' % (self.repo_path, tracking_key))
+            sys.exit(1)
+
 
     # pull any new updates for the repo
     def pull_updates(self):