diff --git a/src/calibre/gui2/tweak_book/preview.py b/src/calibre/gui2/tweak_book/preview.py
index 8083ec051d..e0ed80c8a8 100644
--- a/src/calibre/gui2/tweak_book/preview.py
+++ b/src/calibre/gui2/tweak_book/preview.py
@@ -65,6 +65,7 @@ class ParseWorker(Thread):
         self.requests = Queue()
         self.request_count = 0
         self.parse_items = {}
+        self.launch_error = None
 
     def run(self):
         mod, func = 'calibre.gui2.tweak_book.preview', 'parse_html'
@@ -75,6 +76,7 @@ class ParseWorker(Thread):
         except:
             import traceback
             traceback.print_exc()
+            self.launch_error = traceback.format_exc()
             return
 
         while True:
@@ -530,10 +532,17 @@ class Preview(QWidget):
         self.current_sync_request = None
         self.view.page().go_to_sourceline_address(sourceline_address)
 
+    def report_worker_launch_error(self):
+        if parse_worker.launch_error is not None:
+            tb, parse_worker.launch_error = parse_worker.launch_error, None
+            error_dialog(self, _('Failed to launch worker'), _(
+                'Failed to launch the worker process used for rendering the preview'), det_msg=tb, show=True)
+
     def show(self, name):
         if name != self.current_name:
             self.refresh_timer.stop()
             self.current_name = name
+            self.report_worker_launch_error()
             parse_worker.add_request(name)
             self.view.setUrl(QUrl.fromLocalFile(current_container().name_to_abspath(name)))
             return True
@@ -543,6 +552,7 @@ class Preview(QWidget):
             self.refresh_timer.stop()
             # This will check if the current html has changed in its editor,
             # and re-parse it if so
+            self.report_worker_launch_error()
             parse_worker.add_request(self.current_name)
             # Tell webkit to reload all html and associated resources
             current_url = QUrl.fromLocalFile(current_container().name_to_abspath(self.current_name))