diff --git a/self-host/customize-deployment/configure-lightdash-to-use-external-object-storage.mdx b/self-host/customize-deployment/configure-lightdash-to-use-external-object-storage.mdx
index 4c1c8123..bb887fc3 100644
--- a/self-host/customize-deployment/configure-lightdash-to-use-external-object-storage.mdx
+++ b/self-host/customize-deployment/configure-lightdash-to-use-external-object-storage.mdx
@@ -10,6 +10,10 @@ On Lightdash, we generate some files like:
 
 These files need to be stored in a S3 Compatible Cloud storage. Some options are GCP Buckets, S3 Storage and MinIO.
 
+<Warning>
+  S3-compatible storage is **required**. Lightdash will fail to start if `S3_ENDPOINT`, `S3_BUCKET`, and `S3_REGION` are not set. All warehouses (including Snowflake) fetch async query results from S3.
+</Warning>
+
 ## Configure cloud storage on Google Cloud Platform
 
 Go into GCP: Cloud storage