diff --git a/aqt/profiles.py b/aqt/profiles.py
index a7e206001..1dca866ae 100644
--- a/aqt/profiles.py
+++ b/aqt/profiles.py
@@ -58,6 +58,7 @@ class ProfileManager(object):
         self.name = None
         # instantiate base folder
         self.base = base or self._defaultBase()
+        self.ensureLocalFS()
         self.ensureBaseExists()
         # load metadata
         self.firstRun = self._loadMeta()
@@ -71,6 +72,15 @@ class ProfileManager(object):
     # Base creation
     ######################################################################
 
+    def ensureLocalFS(self):
+        if self.base.startswith("\\\\"):
+            QMessageBox.critical(
+                None, "Error", """\
+To use Anki on a network share, the share must be mapped to a local drive \
+letter. Please see the 'File Locations' section of the manual for more \
+information.""")
+            raise Exception("unc")
+
     def ensureBaseExists(self):
         try:
             self._ensureExists(self.base)