diff --git a/.appveyor.yml b/.appveyor.yml
index 58c14c04c..73d225a15 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -28,7 +28,7 @@ environment:
       CMAKE_CUSTOM_OPTIONS: "-DCMAKE_BUILD_TYPE=Release \
                              -DARCH_OPT=nehalem \
                              -DDEBUG_OUTPUT=ON \
-                             -DENABLE_EXTERNAL_LIBRARIES=ON \
+                             -DENABLE_EXTERNAL_LIBRARIES=AUTO \
                              -DBUILD_SERVER=OFF"
     - TARGET: ubuntu2204docker
       APPVEYOR_BUILD_WORKER_CLOUD: nasrock
@@ -91,15 +91,15 @@ for:
             libbladerf-dev libsoapysdr-dev libiio-dev libuhd-dev \
             python3-mako python3-cheetah python3-numpy \
             autoconf automake libtool ninja-build libclang1-11
-      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES=ON" ]]; then bash cmake/ci/build_cm256cc.sh; fi
-      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES=ON" ]]; then bash cmake/ci/build_mbelib.sh; fi
-      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES=ON" ]]; then bash cmake/ci/build_serialdv.sh; fi
-      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES=ON" ]]; then bash cmake/ci/build_dsdcc.sh; fi
-      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES=ON" ]]; then bash cmake/ci/build_perseus-sdr.sh; fi
-      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES=ON" ]]; then bash cmake/ci/build_xtrx-sdr.sh; fi
-      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES=ON" ]]; then bash cmake/ci/build_airspyhf.sh; fi
-      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES=ON" ]]; then bash cmake/ci/build_rtlsdr.sh; fi
-      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES=ON" ]]; then bash cmake/ci/build_limesuite.sh; fi
+      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES" ]]; then bash cmake/ci/build_cm256cc.sh; fi
+      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES" ]]; then bash cmake/ci/build_mbelib.sh; fi
+      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES" ]]; then bash cmake/ci/build_serialdv.sh; fi
+      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES" ]]; then bash cmake/ci/build_dsdcc.sh; fi
+      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES" ]]; then bash cmake/ci/build_perseus-sdr.sh; fi
+      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES" ]]; then bash cmake/ci/build_xtrx-sdr.sh; fi
+      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES" ]]; then bash cmake/ci/build_airspyhf.sh; fi
+      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES" ]]; then bash cmake/ci/build_rtlsdr.sh; fi
+      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES" ]]; then bash cmake/ci/build_limesuite.sh; fi
       - sh: bash cmake/ci/build_sdrplay.sh
     before_build:
       - sh: bash -c export
diff --git a/debian/rules b/debian/rules
index 1a04209de..da185a490 100755
--- a/debian/rules
+++ b/debian/rules
@@ -3,7 +3,7 @@
 	dh $@ --parallel --buildsystem=cmake+ninja
 
 override_dh_auto_configure:
-	dh_auto_configure -- -DARCH_OPT=nehalem -DENABLE_EXTERNAL_LIBRARIES=ON -DDEBUG_OUTPUT=ON -DBUILD_SERVER=OFF
+	dh_auto_configure -- -DARCH_OPT=nehalem -DENABLE_EXTERNAL_LIBRARIES=AUTO -DDEBUG_OUTPUT=ON -DBUILD_SERVER=OFF
 
 override_dh_auto_test:
 	echo "Skipping test step"
diff --git a/external/CMakeLists.txt b/external/CMakeLists.txt
index 76ed0945f..c28d9d052 100644
--- a/external/CMakeLists.txt
+++ b/external/CMakeLists.txt
@@ -201,7 +201,8 @@ endif (AUTO_EXTERNAL_LIBRARIES)
 
 # Some of the following projects are currently built only for MacOS
 # For WIN32, we use precompiled versions from sdrangel-windows-libraries
-if (APPLE OR LINUX)
+# For LINUX, we require system pacakges to be installed
+if (APPLE)
     set(USE_PRECOMPILED_LIBS FALSE)
 else()
     set(USE_PRECOMPILED_LIBS TRUE)