diff --git a/fixtures/README.md b/fixtures/README.md
index 023af524..6158d7ae 100644
--- a/fixtures/README.md
+++ b/fixtures/README.md
@@ -7,6 +7,9 @@ This directory contains the [test fixtures](https://en.wikipedia.org/wiki/Test_f
 1. Build the project in debug mode: `cargo build`
 2. Execute the runner script in this directory: `./test-fixtures.sh`
 
+On `macOS` you need to have [coreutils](https://www.gnu.org/software/coreutils/) installed to run the script. 
+The simplest way is to install it via [Homebrew](https://brew.sh/): `brew install coreutils`
+
 ### Adding new fixtures
 
 Create an appropriately named directory for the test fixture you want to add. e.g. `test-file-upload`