diff --git a/wsjtx.pro b/wsjtx.pro
index 9fc89ca8b..7f834b893 100644
--- a/wsjtx.pro
+++ b/wsjtx.pro
@@ -14,7 +14,7 @@ VERSION = 1.4
 TEMPLATE = app
 DEFINES = QT5
 QMAKE_CXXFLAGS += -std=c++11
-DEFINES += PROJECT_MANUAL="http://www.physics.princeton.edu/pulsar/K1JT/wsjtx-doc/wsjtx-main.html"
+DEFINES += PROJECT_MANUAL="'\"http://www.physics.princeton.edu/pulsar/K1JT/wsjtx-doc/wsjtx-main.html\"'"
 
 isEmpty (DESTDIR) {
 DESTDIR = ../wsjtx_install