diff --git a/ChangeLog b/ChangeLog
index 87cf746e8..cf0272023 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -35,6 +35,8 @@ Bugs
         to Michele Vetturi).
 - TD-45 Fix preprocessor define (thanks to Jochen Sprickerhof).
 - TW-1282 incorrect URLs in man task-sync (thanks to Jeremiah Marks).
+- TW-1288 Added missing locking for task modifications (thanks to Kosta H,
+          Ralph Bean, Adam Coddington).
 - #1511 sync init crashes if client certification file is empty or invalid
         (thanks to Marton Suranyi).
 - #1508 Show command highlight configuration (thanks to Nicolas Appriou).
diff --git a/src/TDB2.cpp b/src/TDB2.cpp
index a74ab1e4a..475e86568 100644
--- a/src/TDB2.cpp
+++ b/src/TDB2.cpp
@@ -233,6 +233,9 @@ void TF2::commit ()
     {
       if (_file.open ())
       {
+        if (context.config.getBoolean ("locking"))
+          _file.waitForLock ();
+
         // Truncate the file and rewrite.
         _file.truncate ();