diff --git a/app/src/main/assets/logback.xml b/app/src/main/assets/logback.xml
index 97e09b3e4d..d6facdb7dd 100644
--- a/app/src/main/assets/logback.xml
+++ b/app/src/main/assets/logback.xml
@@ -1,6 +1,6 @@
 <configuration>
   <!-- Create a file appender for a log in the application's data directory -->
-  <property name="EXT_FILES_DIR" value="${EXT_DIR:-/sdcard}/Android/data/${PACKAGE_NAME}/files"/>
+  <property scope="context" name="EXT_FILES_DIR" value="${EXT_DIR:-/sdcard}/Android/data/${PACKAGE_NAME}/files"/>
   <appender name="file" class="ch.qos.logback.core.rolling.RollingFileAppender">
     <file>${EXT_FILES_DIR}/AndroidAPS.log</file>
 	<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
diff --git a/app/src/main/java/info/nightscout/androidaps/MainApp.java b/app/src/main/java/info/nightscout/androidaps/MainApp.java
index 711261ca36..455c599c35 100644
--- a/app/src/main/java/info/nightscout/androidaps/MainApp.java
+++ b/app/src/main/java/info/nightscout/androidaps/MainApp.java
@@ -23,6 +23,7 @@ import org.slf4j.LoggerFactory;
 import java.io.File;
 import java.util.ArrayList;
 
+import ch.qos.logback.classic.LoggerContext;
 import info.nightscout.androidaps.Services.Intents;
 import info.nightscout.androidaps.db.DatabaseHelper;
 import info.nightscout.androidaps.interfaces.InsulinInterface;
@@ -201,7 +202,9 @@ public class MainApp extends Application {
             }
         }).start();
 
-        File engineeringModeSemaphore = new File(System.getProperty("EXT_FILES_DIR"),"engineering_mode");
+        LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
+        String extFilesDir = lc.getProperty("EXT_FILES_DIR");
+        File engineeringModeSemaphore = new File(extFilesDir,"engineering_mode");
 
         engineeringMode = engineeringModeSemaphore.exists() && engineeringModeSemaphore.isFile();
         devBranch = BuildConfig.VERSION.contains("dev");