diff --git a/README.md b/README.md
index d785006..a47837f 100644
--- a/README.md
+++ b/README.md
@@ -161,6 +161,16 @@ host using its Docker, not in a socket-less container). See
 [`runner/config.yml`](runner/config.yml) and
 [`runner/forgejo-runner.service`](runner/forgejo-runner.service).
 
+The desktop's **Docker daemon must be running and enabled at boot** — the runner
+builds against it. `docker login` works without the daemon but `docker build`
+won't, so a stopped daemon shows up as *"Cannot connect to the Docker daemon"*
+mid-pipeline. Ensure one daemon owns `/var/run/docker.sock`:
+```sh
+sudo snap stop --disable docker.dockerd      # if a crashing snap docker is present
+sudo systemctl enable --now docker.service   # classic engine, on at boot
+docker info | head                           # verify as your user, no sudo
+```
+
 ### 6. Wire the jb-website repo
 In the `jb-website` repo settings on Forgejo (`Settings → Actions`):