diff --git a/.github/workflows/e2e-tests.yml b/.github/workflows/e2e-tests.yml
index efdfd1a16..4e18b68e8 100644
--- a/.github/workflows/e2e-tests.yml
+++ b/.github/workflows/e2e-tests.yml
@@ -23,10 +23,13 @@ jobs:
       - name: Start MinIO
         run: docker compose up -d minio
 
+      # the bucket, not the health endpoint: MinIO answers health/live while it is still
+      # bootstrapping, so a run whose bucket never got created would only surface much later
+      # as a 500 in the one test that uploads an image
       - name: Wait for MinIO to be ready
         run: |
           for i in {1..30}; do
-            if curl -sf http://127.0.0.1:9000/minio/health/live; then
+            if curl -sf -o /dev/null http://127.0.0.1:9000/sendou/; then
               echo "MinIO is ready"
               exit 0
             fi
diff --git a/compose.yaml b/compose.yaml
index 561853582..3d364e23f 100644
--- a/compose.yaml
+++ b/compose.yaml
@@ -12,9 +12,9 @@ services:
         isAlive() { curl -sf http://127.0.0.1:9000/minio/health/live; }    # check if Minio is alive
         minio $$0 "$$@" --quiet & echo $$! > /tmp/minio.pid                # start Minio in the background
         while ! isAlive; do sleep 0.1; done                                # wait until Minio is alive
-        mc alias set minio http://127.0.0.1:9000 minio-user minio-password # setup Minio client
-        mc mb minio/sendou || true                                         # create a test bucket
-        mc anonymous set public minio/sendou                               # make the test bucket public
+        until mc alias set minio http://127.0.0.1:9000 minio-user minio-password; do sleep 0.5; done # setup Minio client (health/live can answer before credentials are accepted)
+        until mc mb --ignore-existing minio/sendou; do sleep 0.5; done      # create a test bucket
+        until mc anonymous set public minio/sendou; do sleep 0.5; done      # make the test bucket public
         kill -s INT $$(cat /tmp/minio.pid) && rm /tmp/minio.pid            # stop Minio
         while isAlive; do sleep 0.1; done                                  # wait until Minio is stopped
         exec minio $$0 "$$@"                                               # start Minio in the foreground
diff --git a/e2e/global-setup.ts b/e2e/global-setup.ts
index 8ac434fcd..ddab6e3a9 100644
--- a/e2e/global-setup.ts
+++ b/e2e/global-setup.ts
@@ -7,6 +7,9 @@ import { E2E_BASE_PORT, e2eWorkerPort } from "./helpers/playwright";
 const DEBUG = process.env.E2E_DEBUG === "true";
 const SERVER_PROCESSES: ChildProcess[] = [];
 const MINIO_MARKER_FILE = ".e2e-minio-started";
+const STORAGE_BUCKET = "sendou";
+/** Anonymously listable only once the bucket exists and its public policy is set. */
+const MINIO_BUCKET_URL = `http://127.0.0.1:9000/${STORAGE_BUCKET}/`;
 const BUILD_MARKER_FILE = ".e2e-build-marker";
 const BUILD_INPUTS = [
 	"app",
@@ -21,16 +24,26 @@ declare global {
 	var __E2E_SERVERS__: ChildProcess[];
 }
 
+/**
+ * Whether the image storage is usable, which takes more than MinIO answering its health check:
+ * the container bootstraps the bucket only after startup, and a run whose bucket never got created
+ * would otherwise fail deep inside the one test that uploads an image (`art.spec.ts`) with an
+ * opaque 500.
+ */
+async function isMinioBucketReady(): Promise<boolean> {
+	try {
+		const response = await fetch(MINIO_BUCKET_URL);
+		return response.ok;
+	} catch {
+		return false;
+	}
+}
+
 async function waitForMinio(timeout = 60000): Promise<boolean> {
 	const start = Date.now();
 	while (Date.now() - start < timeout) {
-		try {
-			const response = await fetch("http://127.0.0.1:9000/minio/health/live");
-			if (response.ok) {
-				return true;
-			}
-		} catch {
-			// MinIO not ready yet
+		if (await isMinioBucketReady()) {
+			return true;
 		}
 		await new Promise((resolve) => setTimeout(resolve, 1000));
 	}
@@ -39,15 +52,10 @@ async function waitForMinio(timeout = 60000): Promise<boolean> {
 
 async function ensureMinioRunning(): Promise<boolean> {
 	// Check if MinIO is already running
-	try {
-		const response = await fetch("http://127.0.0.1:9000/minio/health/live");
-		if (response.ok) {
-			// biome-ignore lint/suspicious/noConsole: CLI script output
-			console.log("MinIO is already running");
-			return false;
-		}
-	} catch {
-		// MinIO not running, we need to start it
+	if (await isMinioBucketReady()) {
+		// biome-ignore lint/suspicious/noConsole: CLI script output
+		console.log("MinIO is already running");
+		return false;
 	}
 
 	// biome-ignore lint/suspicious/noConsole: CLI script output
@@ -56,7 +64,9 @@ async function ensureMinioRunning(): Promise<boolean> {
 
 	const isReady = await waitForMinio();
 	if (!isReady) {
-		throw new Error("MinIO failed to start within timeout");
+		throw new Error(
+			`MinIO did not become usable within timeout (${MINIO_BUCKET_URL} never answered OK). If MinIO is running, its "${STORAGE_BUCKET}" bucket is missing or not public — recreate the container with "docker compose up -d --force-recreate minio".`,
+		);
 	}
 
 	// biome-ignore lint/suspicious/noConsole: CLI script output
@@ -225,7 +235,7 @@ async function globalSetup(config: FullConfig) {
 					STORAGE_ACCESS_KEY: "minio-user",
 					STORAGE_SECRET: "minio-password",
 					STORAGE_REGION: "us-east-1",
-					STORAGE_BUCKET: "sendou",
+					STORAGE_BUCKET,
 					// no system messages to a shared skalop instance (see build env above)
 					SKALOP_SYSTEM_MESSAGE_URL: "",
 					SKALOP_TOKEN: "",