diff --git a/README.md b/README.md
index cb8ec7f..60a7590 100644
--- a/README.md
+++ b/README.md
@@ -778,6 +778,11 @@ use gf OR gx to open local files as
mkdx uses [g:mkdx#settings.image_extension_pattern](#gmkdxsettingsimage_extension_pattern) to determine
wether or not a file is an image and should be opened by an external application.
+**IMPORTANT**: _mkdx uses `open` behind the scenes, on macOS this will work out of the box,
+on linux make sure the [`xdg-utils`](https://www.freedesktop.org/wiki/Software/xdg-utils/) package
+is installed and that you can run `open https://github.com`.
+`xdg-utils` can be installed by running `sudo apt install xdg-utils` in your terminal._
+
```viml
" :h mkdx-setting-gf-on-steroids
" :h mkdx-mapping-jump-to-file