> For the complete documentation index, see [llms.txt](https://help.enterprise.ledger.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.enterprise.ledger.com/core/transactions/too-large-cluster-error-on-bitcoin-transactions.md). # "Too large cluster" error on Bitcoin transactions A Bitcoin transaction can fail with the status **Failed to broadcast** and an error that mentions `too-large-cluster`. The network refused it. Nothing moved, and the reserved balance returns to the account. #### Why it happens A transaction that spends coins from unconfirmed transactions is linked to them in a **cluster**. Bitcoin nodes refuse any transaction that takes its cluster over 64 transactions or 101 kvB. The usual cause is large incoming transactions, such as deposit sweeps, sent with a very low fee. They stay unconfirmed, and withdrawals that spend their coins go over the limit. Withdrawals that spend only confirmed coins still succeed. A retry will likely fail again. Pause withdrawals from the account until the incoming transactions confirm. To check, look for incoming transactions with 0 confirmations on the account. #### How to solve it * **Wait.** When fees drop, the incoming transactions confirm and the problem clears. This can take hours or days. * **Ask the sender to raise the fee** (Replace-By-Fee). If the transactions come from your own systems, raise the fee there. * **Boost a pending transaction of yours** that spends a stuck incoming transaction. This is Child Pays For Parent: open its **Transaction Details**, click **Boost**, and set a **custom fee** in sat/vB. The fee must cover the parent's size too, so it can be far above the recommended rate. For example, a 250 vB child of a 34,000 vB parent at 1 sat/vB needs about 550 sat/vB to reach 5 sat/vB overall. Click **Finalize** and approve as usual. > **Important:** Do not ask the sender to replace a transaction that one of your pending transactions spends. Your pending transaction would be dropped. #### Prevent it Send deposit sweeps and other large consolidations at a fee rate that matches the network, not the minimum. #### Need help? Raise a ticket on the Service Desk with the ID of the failed transaction and the hashes of the unconfirmed incoming transactions. Sources: * [Bitcoin Magazine on cluster mempool](https://bitcoinmagazine.com/?p=50641) * [Spark mempool policy reference](https://www.spark.money/tools/bitcoin-mempool-policy-reference) --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://help.enterprise.ledger.com/core/transactions/too-large-cluster-error-on-bitcoin-transactions.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.