diff --git a/run.ps1 b/run.ps1
index 412062239a..3b27382468 100644
--- a/run.ps1
+++ b/run.ps1
@@ -179,8 +179,9 @@ if (Test-Path $ConfigFile) {
         }
     }
     catch {
-        Write-Warning "$ConfigFile could not be read. Its settings will be ignored."
-        Write-Warning $Error[0]
+        Write-Host -ForegroundColor Red $Error[0]
+        Write-Error "$ConfigFile contains invalid JSON."
+        exit 1
     }
 }
 
diff --git a/run.sh b/run.sh
index 27e7d7ac6f..02aac15874 100755
--- a/run.sh
+++ b/run.sh
@@ -220,17 +220,28 @@ if [ -f "$config_file" ]; then
             config_channel="$(jq -r 'select(.channel!=null) | .channel' "$config_file")"
             config_tools_source="$(jq -r 'select(.toolsSource!=null) | .toolsSource' "$config_file")"
         else
-            __warn "$config_file is invalid JSON. Its settings will be ignored."
+            _error "$config_file contains invalid JSON."
+            exit 1
         fi
     elif __machine_has python ; then
         if python -c "import json,codecs;obj=json.load(codecs.open('$config_file', 'r', 'utf-8-sig'))" >/dev/null ; then
             config_channel="$(python -c "import json,codecs;obj=json.load(codecs.open('$config_file', 'r', 'utf-8-sig'));print(obj['channel'] if 'channel' in obj else '')")"
             config_tools_source="$(python -c "import json,codecs;obj=json.load(codecs.open('$config_file', 'r', 'utf-8-sig'));print(obj['toolsSource'] if 'toolsSource' in obj else '')")"
         else
-            __warn "$config_file is invalid JSON. Its settings will be ignored."
+            _error "$config_file contains invalid JSON."
+            exit 1
+        fi
+    elif __machine_has python3 ; then
+        if python3 -c "import json,codecs;obj=json.load(codecs.open('$config_file', 'r', 'utf-8-sig'))" >/dev/null ; then
+            config_channel="$(python3 -c "import json,codecs;obj=json.load(codecs.open('$config_file', 'r', 'utf-8-sig'));print(obj['channel'] if 'channel' in obj else '')")"
+            config_tools_source="$(python3 -c "import json,codecs;obj=json.load(codecs.open('$config_file', 'r', 'utf-8-sig'));print(obj['toolsSource'] if 'toolsSource' in obj else '')")"
+        else
+            _error "$config_file contains invalid JSON."
+            exit 1
         fi
     else
-        __warn 'Missing required command: jq or pyton. Could not parse the JSON file. Its settings will be ignored.'
+        _error 'Missing required command: jq or python. Could not parse the JSON file.'
+        exit 1
     fi
 
     [ ! -z "${config_channel:-}" ] && channel="$config_channel"