diff --git a/hgext/journal.py b/hgext/journal.py
--- a/hgext/journal.py
+++ b/hgext/journal.py
@@ -307,7 +307,11 @@
             l = lock.lock(vfs, 'namejournal.lock', 0, desc=desc)
         except error.LockHeld as inst:
             self.ui.warn(
-                _("waiting for lock on %s held by %r\n") % (desc, inst.locker))
+                _("waiting for lock on %s held by %r\n"
+                    """Another Mercurial process seems to be running in
+                     this repository, e.g. an editor opened by 'hg commit'.
+                     Please make sure all processes are terminated then
+                     try again.\n""") % (desc, inst.locker))
             # default to 600 seconds timeout
             l = lock.lock(
                 vfs, 'namejournal.lock',
diff --git a/mercurial/lock.py b/mercurial/lock.py
--- a/mercurial/lock.py
+++ b/mercurial/lock.py
@@ -113,11 +113,19 @@
         # show more details for new-style locks
         if ':' in locker:
             host, pid = locker.split(":", 1)
-            msg = (_("waiting for lock on %s held by process %r on host %r\n")
+            msg = (_("waiting for lock on %s held by process %r on host %r\n"
+                    """Another Mercurial process seems to be running in
+                     this repository, e.g. an editor opened by 'hg commit'.
+                     Please make sure all processes are terminated then
+                     try again.\n""")
                    % (pycompat.bytestr(l.desc), pycompat.bytestr(pid),
                       pycompat.bytestr(host)))
         else:
-            msg = (_("waiting for lock on %s held by %r\n")
+            msg = (_("waiting for lock on %s held by %r\n"
+                 """Another Mercurial process seems to be running in
+                     this repository, e.g. an editor opened by 'hg commit'.
+                     Please make sure all processes are terminated then
+                     try again.\n""")
                    % (l.desc, pycompat.bytestr(locker)))
         printer(msg)
 
diff --git a/tests/test-lock-badness.t b/tests/test-lock-badness.t
--- a/tests/test-lock-badness.t
+++ b/tests/test-lock-badness.t
@@ -15,17 +15,17 @@
 
   $ cat > testlock.py << EOF
   > from mercurial import error, registrar
-  > 
+  >
   > cmdtable = {}
   > command = registrar.command(cmdtable)
-  > 
+  >
   > def acquiretestlock(repo, releaseexc):
   >     def unlock():
   >         if releaseexc:
   >             raise error.Abort(b'expected release exception')
   >     l = repo._lock(repo.vfs, b'testlock', False, unlock, None, b'test lock')
   >     return l
-  > 
+  >
   > @command(b'testlockexc')
   > def testlockexc(ui, repo):
   >     testlock = acquiretestlock(repo, True)