diff --git a/src/blackmisc/loghandler.cpp b/src/blackmisc/loghandler.cpp
index f7ba37dc7..cfe8ffff5 100644
--- a/src/blackmisc/loghandler.cpp
+++ b/src/blackmisc/loghandler.cpp
@@ -25,7 +25,7 @@
 #include <tuple>
 
 #ifdef Q_OS_WIN
-#include <Windows.h>
+#include <windows.h>
 #endif
 
 namespace BlackMisc
diff --git a/src/blackmisc/simulation/fsx/simconnectutilities.h b/src/blackmisc/simulation/fsx/simconnectutilities.h
index 7364af109..bea0ba4ec 100644
--- a/src/blackmisc/simulation/fsx/simconnectutilities.h
+++ b/src/blackmisc/simulation/fsx/simconnectutilities.h
@@ -31,7 +31,7 @@
 #   ifndef NOMINMAX
 #       define NOMINMAX
 #   endif
-#   include <Windows.h>
+#   include <windows.h>
 #else
 using DWORD = unsigned long; //!< Fake Windows DWORD
 #endif
diff --git a/src/blackmisc/simulation/xplane/xplaneutil.cpp b/src/blackmisc/simulation/xplane/xplaneutil.cpp
index 10781ec34..9fbef7beb 100644
--- a/src/blackmisc/simulation/xplane/xplaneutil.cpp
+++ b/src/blackmisc/simulation/xplane/xplaneutil.cpp
@@ -18,7 +18,7 @@
 #include <QTextStream>
 
 #if defined(Q_OS_WIN)
-#include <Shlobj.h>
+#include <shlobj.h>
 #endif
 
 using namespace BlackMisc;
diff --git a/src/blackmisc/windllutils.cpp b/src/blackmisc/windllutils.cpp
index 17c868af8..973ca9511 100644
--- a/src/blackmisc/windllutils.cpp
+++ b/src/blackmisc/windllutils.cpp
@@ -13,7 +13,7 @@
 #include <QCoreApplication>
 
 #ifdef Q_OS_WIN
-#include <Windows.h>
+#include <windows.h>
 #include <tlhelp32.h>
 #endif
 
diff --git a/src/blackmisc/worker.cpp b/src/blackmisc/worker.cpp
index 0caf4cf83..9356c45e8 100644
--- a/src/blackmisc/worker.cpp
+++ b/src/blackmisc/worker.cpp
@@ -15,7 +15,7 @@
 #include <QPointer>
 
 #ifdef Q_OS_WIN32
-#include <Windows.h>
+#include <windows.h>
 #endif
 
 namespace BlackMisc