An address can be missing from a restored Bitcoin wallet because the software stopped looking too early. BIP44 describes a search that ends after 20 consecutive unused external addresses. Electrum documents how addresses beyond its gap limit can be recovered. A numbered example makes the stopping point visible.
| What you need to know |
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| BIP44 stops external address discovery after 20 consecutive unused addresses. |
| Its discovery rule checks transaction history, rather than an address's current balance. |
| Electrum warns that addresses generated beyond its gap limit are not automatically recovered from the seed. |
| Electrum describes extending the search by increasing the gap limit or generating more addresses. |
Address 21 sits beyond twenty unused addresses
In the BIP44 specification, the gap is a sequence of unused addresses on the external chain, which supplies receiving addresses. Once the software encounters 20 in a row, it assumes there are no used addresses farther along that chain. The number is a discovery rule in this specification; it should not be treated as a universal setting for every wallet.
Consider a hypothetical receiving-address sequence numbered from zero.
Address 0 has transaction history, addresses 1 through 20 have never been used, and address 21 received bitcoin. A search following that 20-address rule stops at address 20. It does not reach address 21, even though the example explicitly places funds there. The limit describes how far the software looked.
Now change one detail: address 10 previously received bitcoin, but its current balance is zero.
That history breaks the unused sequence. Addresses 11 through 20 form a run of only ten unused addresses, so the same search can continue to address 21. Substituting “zero balance” for “unused” would give the wrong result.
Extending the search in Electrum
The official Electrum FAQ warns that addresses generated beyond the gap limit will not automatically be recovered from the seed. It describes two ways to reach them: increase the client’s gap limit or generate further addresses until the used addresses are found. Its separate gap-limit explanation describes 20 as the default in Electrum 2.0, so check the documentation for the version you are actually restoring into.
The two sources clarify different parts of the same problem. BIP44 explains why transaction history makes discovery continue; Electrum explains why deliberately generating addresses beyond a search limit creates extra recovery work. Successfully loading a seed therefore does not, by itself, establish that every previously generated receiving address was searched.
For this example, the recovery target is address 21. Check whether the restored wallet searched that far, then follow the procedure for the wallet and version in use to extend the search. That gives the recovery attempt a testable destination. Other causes, such as different derivation choices or settings, require their own checks if extending the address search does not recover the expected history.
