From 774042665b05596249f41898a19d7b4f84ab013d Mon Sep 17 00:00:00 2001
From: warcanoid <41340203+warcanoid@users.noreply.github.com>
Date: Thu, 20 Jun 2019 19:29:07 +0200
Subject: [PATCH] Update installation.markdown (#9613)

* Update installation.markdown

* :pencil2: Tweaks
---
 source/_docs/z-wave/installation.markdown | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/source/_docs/z-wave/installation.markdown b/source/_docs/z-wave/installation.markdown
index 575e5fadac3..cf95b4f3746 100644
--- a/source/_docs/z-wave/installation.markdown
+++ b/source/_docs/z-wave/installation.markdown
@@ -227,6 +227,18 @@ $ ls /dev/cu.usbmodem*
 
 If your device path changes when you restart, see [this guide](http://hintshop.ludvig.co.nz/show/persistent-names-usb-serial-devices/) on fixing it.
 
+## {% linkable_title Ubuntu and Debian based host system %}
+
+If your instance is running on a Debian based system, e.g., Ubuntu, the ModemManager may cause unexpected issues.
+
+The ModemManager might be claiming or interfering with a USB Z-Wave stick, like the much used Aeotec ones. If you experience issues where the stick stops responding, needs to be re-plugged or Home Assistant needs a restart to get Z-Wave back, chances are high that the ModemManager is causing the issue.
+
+ Execute the following command on your host system to disable the ModemManager:
+
+ ```bash
+systemctl disable ModemManager.service
+```
+
 ### {% linkable_title Component could not be set up %}
 
 Sometimes the device may not be accessible and you'll get an error message upon startup about not being able to set up Z-Wave. Run the following command for your device path (here we're using `/dev/ttyAMA0` for our Razberry board):