diff --git a/docs/setup/installation.md b/docs/setup/installation.md
index fb64c9ba4d3..3d000755f85 100644
--- a/docs/setup/installation.md
+++ b/docs/setup/installation.md
@@ -326,6 +326,17 @@ Some extra dependencies may be needed. You can use Homebrew (https://brew.sh) fo
 You may need to install icu, and make the icu binaries and libraries accessible.
 Please follow [the official instructions of PyICU](https://pypi.org/project/PyICU/) to do so.
 
+If you're struggling to get icu discovered, and see:
+```
+  RuntimeError:
+  Please install pkg-config on your system or set the ICU_VERSION environment
+  variable to the version of ICU you have installed.
+```
+despite it being installed and having your `PATH` updated, you can omit this dependency by
+not specifying `--extras all` to `poetry`. If using postgres, you can install Synapse via
+`poetry install  --extras postgres`. ICU is not a hard dependency on getting a working
+installation.
+
 On ARM-based Macs you may also need to install libjpeg and libpq:
 ```sh
  brew install jpeg libpq