diff --git a/HISTORY.rst b/HISTORY.rst
index 9bd66af6..463e45db 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -15,7 +15,8 @@ Release History
   *MCUs* (`issue #35 <https://github.com/ivankravets/platformio/issues/35>`_)
 * Automatic detection of port on `platformio serialports monitor <http://docs.platformio.ikravets.com/en/latest/userguide/cmd_serialports.html#platformio-serialports-monitor>`_
   (`issue #37 <https://github.com/ivankravets/platformio/issues/37>`_)
-* Fixed urllib3's *SSL* warning under Python <= 2.7.2  (`issue #39 <https://github.com/ivankravets/platformio/issues/39>`_)
+* Allowed auto-installation of platforms when prompts are disabled (`issue #43 <https://github.com/ivankravets/platformio/issues/43>`_)
+* Fixed urllib3's *SSL* warning under Python <= 2.7.2 (`issue #39 <https://github.com/ivankravets/platformio/issues/39>`_)
 * Fixed bug with *Arduino USB* boards (`issue #40 <https://github.com/ivankravets/platformio/issues/40>`_)
 
 0.9.2 (2014-12-10)
diff --git a/platformio/commands/run.py b/platformio/commands/run.py
index c45f61d6..2458b3bb 100644
--- a/platformio/commands/run.py
+++ b/platformio/commands/run.py
@@ -68,10 +68,12 @@ def process_environment(ctx, name, options, targets, upload_port):
 
     telemetry.on_run_environment(options, envtargets)
 
-    if (app.get_setting("enable_prompts") and
-            platform not in PlatformFactory.get_platforms(installed=True) and
+    installed_platforms = PlatformFactory.get_platforms(
+        installed=True).keys()
+    if (platform not in installed_platforms and (
+            not app.get_setting("enable_prompts") or
             click.confirm("The platform '%s' has not been installed yet. "
-                          "Would you like to install it now?" % platform)):
+                          "Would you like to install it now?" % platform))):
         ctx.invoke(cmd_install, platforms=[platform])
 
     p = PlatformFactory.newPlatform(platform)
diff --git a/platformio/commands/show.py b/platformio/commands/show.py
index de8769bb..989b9aaf 100644
--- a/platformio/commands/show.py
+++ b/platformio/commands/show.py
@@ -21,7 +21,7 @@ def cli(ctx, platform):
         installed=True).keys()
 
     if platform not in installed_platforms:
-        if (app.get_setting("enable_prompts") and
+        if (not app.get_setting("enable_prompts") or
                 click.confirm("The platform '%s' has not been installed yet. "
                               "Would you like to install it now?" % platform)):
             ctx.invoke(cmd_install, platforms=[platform])