diff --git a/README.md b/README.md
index 856eab5e..2386829f 100644
--- a/README.md
+++ b/README.md
@@ -71,6 +71,15 @@ Currently the easiest way to install Home Manager is as follows:
 
     if you follow a Nixpkgs version 18.09 channel.
 
+    On NixOS you may need to log out and back in for the channel to
+    become available. On non-NixOS you may have to add
+
+    ```shell
+    export NIX_PATH=$HOME/.nix-defexpr/channels${NIX_PATH:+:}$NIX_PATH
+    ```
+
+    to your shell (see [nix#2033](https://github.com/NixOS/nix/issues/2033)).
+
 3.  Install Home Manager and create the first Home Manager generation:
 
     ```console
diff --git a/doc/installation.xml b/doc/installation.xml
index 53294755..ea3c49fa 100644
--- a/doc/installation.xml
+++ b/doc/installation.xml
@@ -85,6 +85,15 @@ $ nix-channel --update
     <para>
      if you follow a Nixpkgs version 18.09 channel.
     </para>
+    <para>
+     On NixOS you may need to log out and back in for the channel to
+     become available. On non-NixOS you may have to add
+<programlisting>
+export NIX_PATH=$HOME/.nix-defexpr/channels${NIX_PATH:+:}$NIX_PATH
+</programlisting>
+     to your shell (see
+     <link xlink:href="https://github.com/NixOS/nix/issues/2033">nix#2033</link>).
+    </para>
    </listitem>
    <listitem>
     <para>