diff --git a/website/docs/r/backup_policy_vm.html.markdown b/website/docs/r/backup_policy_vm.html.markdown
index 49fb62ba3972..108b2c0f3979 100644
--- a/website/docs/r/backup_policy_vm.html.markdown
+++ b/website/docs/r/backup_policy_vm.html.markdown
@@ -79,6 +79,8 @@ The following arguments are supported:
 
 * `instant_restore_retention_days` - (Optional) Specifies the instant restore retention range in days. Possible values are between `1` and `5` when `policy_type` is `V1`, and `1` to `30` when `policy_type` is `V2`.
 
+~> **NOTE:** `instant_restore_retention_days` **must** be set to `5` if the backup frequency is set to `Weekly`.
+
 * `instant_restore_resource_group` - (Optional) Specifies the instant restore resource group name as documented in the `instant_restore_resource_group` block below.
 
 * `retention_daily` - (Optional) Configures the policy daily retention as documented in the `retention_daily` block below. Required when backup frequency is `Daily`.