<p>No, if the transaction is valid then it can always be included in a block if a valid nonce/extra nonce is found.</p>

CC BY-SA 3.0
2017-11-26T10:00:55.393Z
2017-11-26T10:00:55.393Z
meshcollider
<p>If you mean that the transaction may be pending for hours, or even days, yes: <a href="https://en.bitcoin.it/wiki/Transaction_expiration" rel="nofollow noreferrer">it can happen</a> and it's part of Bitcoin Core protocol.</p>

<p>You may also want to have a look at <a href="https://bitcoin.stackexchange.com/questions/53852/how-to-unstuck-a-low-fee-transaction-with-blockchain-info">this question</a></p>

CC BY-SA 3.0
2017-11-30T08:44:06.550Z
2017-11-30T08:44:06.550Z
Xavier Quintana
<p>No. By the definition, any valid transaction can be placed in block. If something in block invalidates it - this is only an array of random bytes, not a valid bitcoin transaction.</p>

CC BY-SA 3.0
2017-11-26T12:22:43.750Z
2017-11-26T12:22:43.750Z
amaclin
<p>Is it possible to have a "unlucky" transaction that can never be part of block? Meaning grouping it with other transactions never results in a valid block?</p>

<p>[Edit]
By not being in valid block, I meant no valid nonce is found with given target difficulty. It seems mathematically, this is possible and what happens to transaction (if there is no expirey) in this case?</p>

CC BY-SA 3.0
2017-11-26T10:58:49.320Z
The number of possible blocks including that transaction is a number with tens of thousands of digits. You're imagining there would be no possible nonce for any of them?
David Schwartz
<transactions><blockchain><unconfirmed-transactions><block>
Transactions that cannot be part of block
vent
# Transactions that cannot be part of block

(Asked by: username_0 on 2017-11-26)

Is it possible to have a "unlucky" transaction that can never be part of block? Meaning grouping it with other transactions never results in a valid block?

[Edit]
By not being in valid block, I meant no valid nonce is found with given target difficulty. It seems mathematically, this is possible and what happens to transaction (if there is no expirey) in this case?

**Tags:** transactions, blockchain, unconfirmed-transactions, block

> **Comments:**
> **username_1**: The number of possible blocks including that transaction is a number with tens of thousands of digits. You're imagining there would be no possible nonce for any of them?  

---

## 3 answers

### Answer by username_2 on 2017-11-26. Score: 2

No, if the transaction is valid then it can always be included in a block if a valid nonce/extra nonce is found.


---

### Answer by username_3 on 2017-11-30. Score: 1

If you mean that the transaction may be pending for hours, or even days, yes: [it can happen](https://en.bitcoin.it/wiki/Transaction_expiration) and it's part of Bitcoin Core protocol.

You may also want to have a look at [this question](https://bitcoin.stackexchange.com/questions/53852/how-to-unstuck-a-low-fee-transaction-with-blockchain-info)


---

### Answer by username_4 on 2017-11-26. Score: 1

No. By the definition, any valid transaction can be placed in block. If something in block invalidates it - this is only an array of random bytes, not a valid bitcoin transaction.


---

