diff --git a/Source/CLI/CLI.cpp b/Source/CLI/CLI.cpp
index ae36ed99..01307e34 100644
--- a/Source/CLI/CLI.cpp
+++ b/Source/CLI/CLI.cpp
@@ -123,7 +123,14 @@ void Log_0(struct MediaInfo_Event_Log_0* Event)
 
             // If no Implementation Schema registered, use one by default
             if (!MCL.get_implementation_schema_file().length())
-                MCL.create_default_implementation_schema();
+            {
+                if (MCL.create_default_implementation_schema(err) != 0)
+                {
+                    if (err == "Unable to write implementation schema file.")
+                        err += " Check write permissions on MediaConch data directory.";
+                    return CLI_RETURN_ERROR;
+                }
+            }
 
             if (!MCL.ReportAndFormatCombination_IsValid(files, report_set, display_content,
                                                         format, err))
diff --git a/Source/Common/Core.cpp b/Source/Common/Core.cpp
index 01dc3274..a5cb3e60 100644
--- a/Source/Common/Core.cpp
+++ b/Source/Common/Core.cpp
@@ -224,7 +224,7 @@ const std::string& Core::get_implementation_schema_file()
 }
 
 //---------------------------------------------------------------------------
-void Core::create_default_implementation_schema()
+int Core::create_default_implementation_schema(std::string& err)
 {
     std::string path = get_local_data_path();
     std::string file = path + "MatroskaSchema.xml";
@@ -233,12 +233,17 @@ void Core::create_default_implementation_schema()
     ofs.open(file.c_str(), std::ofstream::out | std::ofstream::binary);
 
     if (!ofs.is_open())
-        return;
+    {
+        err = "Unable to write implementation schema file.";
+        return -1;
+    }
 
     ofs << xsl_schema_matroska_schema;
     ofs.close();
 
     set_implementation_schema_file(file);
+
+    return 0;
 }
 
 //---------------------------------------------------------------------------
diff --git a/Source/Common/Core.h b/Source/Common/Core.h
index 01509906..2358d78f 100644
--- a/Source/Common/Core.h
+++ b/Source/Common/Core.h
@@ -160,7 +160,7 @@ class Core
     const std::map<std::string, std::string>& get_implementation_options() const;
     void               set_implementation_schema_file(const std::string& file);
     const std::string& get_implementation_schema_file();
-    void               create_default_implementation_schema();
+    int                create_default_implementation_schema(std::string& err);
     void               set_implementation_verbosity(const std::string& verbosity);
     const std::string& get_implementation_verbosity();
     void               set_compression_mode(MediaConchLib::compression compress);
diff --git a/Source/Common/MediaConchLib.cpp b/Source/Common/MediaConchLib.cpp
index 87c108f5..db1dff10 100644
--- a/Source/Common/MediaConchLib.cpp
+++ b/Source/Common/MediaConchLib.cpp
@@ -733,9 +733,9 @@ const std::string& MediaConchLib::get_implementation_schema_file()
 }
 
 //---------------------------------------------------------------------------
-void MediaConchLib::create_default_implementation_schema()
+int MediaConchLib::create_default_implementation_schema(std::string& err)
 {
-    core->create_default_implementation_schema();
+    return core->create_default_implementation_schema(err);
 }
 
 //---------------------------------------------------------------------------
diff --git a/Source/Common/MediaConchLib.h b/Source/Common/MediaConchLib.h
index 6d9c516d..051b7784 100644
--- a/Source/Common/MediaConchLib.h
+++ b/Source/Common/MediaConchLib.h
@@ -369,7 +369,7 @@ class MediaConchLib
     // Implementation checker arguments
     void               set_implementation_schema_file(const std::string& file);
     const std::string& get_implementation_schema_file();
-    void               create_default_implementation_schema();
+    int                create_default_implementation_schema(std::string& err);
     void               set_implementation_verbosity(const std::string& verbosity);
     const std::string& get_implementation_verbosity();
 
diff --git a/Source/Daemon/Daemon.cpp b/Source/Daemon/Daemon.cpp
index 26cbcae7..d24b415d 100644
--- a/Source/Daemon/Daemon.cpp
+++ b/Source/Daemon/Daemon.cpp
@@ -73,7 +73,13 @@ namespace MediaConch
 
         // If no Implementation Schema registered, use one by default
         if (!MCL->get_implementation_schema_file().length())
-            MCL->create_default_implementation_schema();
+        {
+            if (MCL->create_default_implementation_schema(err) != 0)
+            {
+                std::clog << err << std::endl;
+                return -1;
+            }
+        }
 
         // Load policy
         MCL->load_system_policy();
diff --git a/Source/GUI/Qt/mainwindow.cpp b/Source/GUI/Qt/mainwindow.cpp
index e5f23ca0..888b4a9d 100644
--- a/Source/GUI/Qt/mainwindow.cpp
+++ b/Source/GUI/Qt/mainwindow.cpp
@@ -89,7 +89,20 @@ MainWindow::MainWindow(QWidget *parent) :
 
     // Core configuration
     if (!MCL.get_implementation_schema_file().length())
-        MCL.create_default_implementation_schema();
+    {
+        if (MCL.create_default_implementation_schema(err) != 0)
+        {
+            if (err == "Unable to write implementation schema file.")
+                err += "\nCheck write permissions on MediaConch data directory.";
+
+            QMessageBox msgBox(QMessageBox::Critical, tr("Initialisation error"),
+                       QString().fromStdString(err), QMessageBox::Abort, parent);
+
+            msgBox.exec();
+            close();
+        }
+    }
+
     int nb_threads=QThread::idealThreadCount();
     if (nb_threads!=-1)
         MCL.set_default_scheduler_max_threads(nb_threads);