diff --git a/hgext/largefiles/remotestore.py b/hgext/largefiles/remotestore.py
--- a/hgext/largefiles/remotestore.py
+++ b/hgext/largefiles/remotestore.py
@@ -52,7 +52,7 @@
         except IOError as e:
             raise error.Abort(
                 _('remotestore: could not open file %s: %s')
-                % (filename, str(e)))
+                % (filename, util.forcebytestr(e)))
 
     def _getfile(self, tmpfile, filename, hash):
         try:
@@ -60,7 +60,8 @@
         except urlerr.httperror as e:
             # 401s get converted to error.Aborts; everything else is fine being
             # turned into a StoreError
-            raise basestore.StoreError(filename, hash, self.url, str(e))
+            raise basestore.StoreError(filename, hash, self.url,
+                                       util.forcebytestr(e))
         except urlerr.urlerror as e:
             # This usually indicates a connection problem, so don't
             # keep trying with the other files... they will probably
@@ -68,7 +69,8 @@
             raise error.Abort('%s: %s' %
                              (util.hidepassword(self.url), e.reason))
         except IOError as e:
-            raise basestore.StoreError(filename, hash, self.url, str(e))
+            raise basestore.StoreError(filename, hash, self.url,
+                                       util.forcebytestr(e))
 
         return lfutil.copyandhash(chunks, tmpfile)