diff --git a/CMakeLists.txt b/CMakeLists.txt
index 160edfa..08f519c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,31 @@
-project(rclone-browser)
+# CMake 3.5 is required for compatibility with modern CMake versions (4.0+)
+# which removed support for projects requiring < 3.5. CMake 3.5 was released
+# in 2016 and should be available on all supported platforms via package
+# managers (Homebrew, etc.) or direct download.
+# Note: This does NOT affect the minimum macOS version the app can run on
+# (controlled by CMAKE_OSX_DEPLOYMENT_TARGET in src/CMakeLists.txt).
+
+# Check CMake version and provide helpful error message if too old
+if(CMAKE_VERSION VERSION_LESS "3.5")
+    message(FATAL_ERROR "\n"
+        "CMake 3.5 or higher is required to build this project.\n"
+        "Your current CMake version is: ${CMAKE_VERSION}\n\n"
+        "To install CMake 3.5+ on your system:\n"
+        "  macOS (Homebrew):     brew install cmake\n"
+        "  macOS (MacPorts):     sudo port install cmake\n"
+        "  Linux (Ubuntu/Debian): sudo apt-get install cmake\n"
+        "  Linux (Fedora/RHEL):   sudo dnf install cmake\n"
+        "  Linux (Arch):          sudo pacman -S cmake\n"
+        "  Windows:               Download from https://cmake.org/download/\n"
+        "  Or build from source:  https://cmake.org/download/\n\n"
+        "After installing, make sure the new CMake is in your PATH.\n"
+        "You can verify with: cmake --version\n"
+    )
+endif()
 
-cmake_minimum_required(VERSION 2.8)
+cmake_minimum_required(VERSION 3.5)
+
+project(rclone-browser)
 
 if(WIN32)
   # link automatically to qtmain.lib on Windows
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 321ea72..e5b511c 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,11 +1,8 @@
-cmake_minimum_required(VERSION 2.8)
+# cmake_minimum_required is set in parent CMakeLists.txt
 
-if (NOT ${CMAKE_VERSION} VERSION_LESS "3.0.0")
-	cmake_policy(SET CMP0028 NEW)
-endif()
-if (NOT ${CMAKE_VERSION} VERSION_LESS "2.8.11")
-	cmake_policy(SET CMP0020 NEW)
-endif()
+# Set policies for compatibility
+cmake_policy(SET CMP0028 NEW)
+cmake_policy(SET CMP0020 NEW)
 
 if(WIN32)
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4 /WX /wd4100 /wd4189")