diff --git a/docs/learn/storage/block-sync.md b/docs/learn/storage/block-sync.md
index 6e7621e9bfcb..31cffe22bf48 100644
--- a/docs/learn/storage/block-sync.md
+++ b/docs/learn/storage/block-sync.md
@@ -57,4 +57,8 @@ Chaindata snapshots offer a faster alternative to Full Sync. A snapshot is a com
 
 ## Snap Sync
 
-Currently, Kaia nodes do not support the [Snap Sync](https://geth.ethereum.org/docs/fundamentals/sync-modes) method. However, using a chaindata snapshot provides a comparable advantage in terms of faster initial synchronization.
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+Currently, Kaia nodes do not support the [Snap Sync](https://geth.ethereum.org/docs/fundamentals/sync-modes) method. However, using a chaindata snapshot provides a comparable advantage in terms of faster initial synchronization.
+
+## Fast Sync
+
+Kaia nodes do not support the Fast Sync method. A node started with `--syncmode fast` exits with an error at startup. Use Full Sync or a chaindata snapshot instead.
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