diff --git a/Assistant/Threads/Exporter.hs b/Assistant/Threads/Exporter.hs
index 747e919da7..6a43954bcb 100644
--- a/Assistant/Threads/Exporter.hs
+++ b/Assistant/Threads/Exporter.hs
@@ -64,6 +64,7 @@ exportToRemotes rs = do
 			Annex.changeState $ \st -> st { Annex.errcounter = 0 }
 			start <- liftIO getCurrentTime
 			void $ Command.Sync.seekExportContent rs
+				=<< join Command.Sync.getCurrBranch
 			-- Look at command error counter to see if the export
 			-- didn't work.
 			failed <- (> 0) <$> Annex.getState Annex.errcounter
diff --git a/CHANGELOG b/CHANGELOG
index 51e6590f51..5b7221e9d4 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,10 @@
+git-annex (6.20180927) UNRELEASED; urgency=medium
+
+  * sync: Warn when a remote's export is not updated to the current
+    tree because export tracking is not configured.
+
+ -- Joey Hess <id@joeyh.name>  Thu, 27 Sep 2018 15:27:20 -0400
+
 git-annex (6.20180926) upstream; urgency=medium
 
   [ Joey Hess ]
diff --git a/Command/Sync.hs b/Command/Sync.hs
index 52fa929ee8..39187ed939 100644
--- a/Command/Sync.hs
+++ b/Command/Sync.hs
@@ -189,7 +189,7 @@ seek o = allowConcurrentOutput $ do
 			
 			whenM shouldsynccontent $ do
 				syncedcontent <- seekSyncContent o dataremotes
-				exportedcontent <- seekExportContent exportremotes
+				exportedcontent <- withbranch $ seekExportContent exportremotes
 				-- Transferring content can take a while,
 				-- and other changes can be pushed to the
 				-- git-annex branch on the remotes in the
@@ -680,22 +680,39 @@ syncFile ebloom rs af k = onlyActionOn' k $ do
  - 
  - Returns True if any file transfers were made.
  -}
-seekExportContent :: [Remote] -> Annex Bool
-seekExportContent rs = or <$> forM rs go
+seekExportContent :: [Remote] -> CurrBranch -> Annex Bool
+seekExportContent rs (currbranch, _) = or <$> forM rs go
   where
 	go r = withExclusiveLock (gitAnnexExportLock (Remote.uuid r)) $ do
 		db <- Export.openDb (Remote.uuid r)
 		ea <- Remote.exportActions r
 		exported <- case remoteAnnexExportTracking (Remote.gitconfig r) of
-			Nothing -> getExport (Remote.uuid r)
+			Nothing -> nontracking r
 			Just b -> do
 				mcur <- inRepo $ Git.Ref.tree b
 				case mcur of
-					Nothing -> getExport (Remote.uuid r)
+					Nothing -> nontracking r
 					Just cur -> do
 						Command.Export.changeExport r ea db cur
 						return [Exported cur []]
 		Export.closeDb db `after` fillexport r ea db exported
+		
+	nontracking r = do
+		exported <- getExport (Remote.uuid r)
+		maybe noop (warnnontracking r exported) currbranch
+		return exported
+	
+	warnnontracking r exported currb = inRepo (Git.Ref.tree currb) >>= \case
+		Just currt | not (any (\ex -> exportedTreeish ex == currt) exported) ->
+			showLongNote $ unwords
+				[ "Not updating export to " ++ Remote.name r
+				, "to reflect changes to the tree, because export"
+				, "tracking is not enabled. "
+				, "(Use git-annex export's --tracking option"
+				, "to enable it.)"
+				]
+		_ -> noop
+
 
 	fillexport _ _ _ [] = return False
 	fillexport r ea db (Exported { exportedTreeish = t }:[]) =
diff --git a/doc/git-annex-export.mdwn b/doc/git-annex-export.mdwn
index 95f56e024b..6c963990b3 100644
--- a/doc/git-annex-export.mdwn
+++ b/doc/git-annex-export.mdwn
@@ -43,7 +43,7 @@ versions of files stored in them. If a special remote is set up to do
 that, it can be used as a key/value store and the limitations in the above
 paragraph do not appy. Note that dropping content from such a remote is
 not supported. See individual special remotes' documentation for
-details of how to  enable such versioning.
+details of how to enable such versioning.
 
 # OPTIONS
 
@@ -55,7 +55,11 @@ details of how to  enable such versioning.
 
   This makes the export track changes that are committed to
   the branch. `git annex sync --content` and the git-annex assistant
-  will update exports when it commits to the branch they are tracking.
+  will update exports with commits made to the branch.
+
+  This is a local configuration setting, similar to a git remote's tracking
+  branch. You'll need to run `git annex export --tracking` in each
+  repository you want the export to track.
 
 * `--fast`
 
diff --git a/doc/todo/sync_to_non_tracking_export_confusing.mdwn b/doc/todo/sync_to_non_tracking_export_confusing.mdwn
index 3a4bfe6255..2f67fed5d8 100644
--- a/doc/todo/sync_to_non_tracking_export_confusing.mdwn
+++ b/doc/todo/sync_to_non_tracking_export_confusing.mdwn
@@ -17,3 +17,5 @@ have a tracking branch, to help the user understand why it's not syncing
 their recent changes to it.
 
 --[[Joey]] 
+
+> [[done]] --[[Joey]]