Concepts · Backup versus original
The difference between the backup and the wallet itself
«I have a backup» can mean two completely different things depending on the era and the type of wallet. In one case you have everything; in the other, you have an old photograph of something that later changed.
Backups that contain everything
If your backup is a recovery phrase, it contains the entire wallet: all accounts, all addresses and every address created in future. It doesn’t expire and never goes out of date. It doesn’t matter that you wrote it down in 2017 and used the wallet until yesterday: the phrase still opens everything.
That is what makes the word system so convenient and why it took over: a single backup, made once, is good forever.
Backups that are a snapshot
In older wallets, predating the word system, the backup was a file with the keys that existed that day. Bitcoin Core, for example, kept a pool of a hundred ready-made addresses: as you spent them it created more, and those new ones were not in your backup.
How to tell which case you are in
| Your backup is… | What it contains |
|---|---|
| Twelve or twenty-four words | The whole wallet, forever |
| A key starting with xprv | The whole wallet, forever |
| A file from a modern wallet | Normally everything |
| A wallet.dat from before 2013 | Only what existed that day |
| A loose private key | Only one address |
| A screenshot of the balance | Nothing: it is not a backup |
What to do if you are in the second case
- Look for the most recent copy you have, not the first one you find.
- Check drives, USB sticks, emails and cloud folders in case there are several versions.
- Compare the dates: you want the last one, from just before you stopped using the wallet.
- If you only have an old copy and the balance shows zero, check your addresses’ history on an explorer: it will tell you where the money went.