Use Rescan when you want to reset all your accounts and scan the blockchain data from a given point in time / height.
This is particularly useful if you have an issue with your wallet and want to reset it, but also when you import an old account and want to recover its balance.
The synchronization data is deleted but your accounts are kept. Then the wallet starts downloading and scanning blocks from the given height.
If you have multiple accounts, make sure you enter a height that is lower than the height of the first transaction (of every account).
Scanning updates all the accounts at once. If you want to rescan multiple new accounts, it is much better to first, create them all and then rescan one time.
There was a period of very large blocks from Jul 2023 to Oct 2024. If your wallet was created after this period, make sure you enter the right height/date. Otherwise it will spend a lot of time processing these blocks needlessly.
- By date
- By height
Resetting an account does not make you lose your funds since they are recorded on the blockchain.
Resetting an account means deleting its synchronization data. The balance is reset and the blocks have to be scanned to look for the available funds.
Birth Height
The birth height of an account is the block height when the account was created. Better yet, it is the height when the first transaction was received.
By definition, there are no transactions before the birth height and therefore when the account is rescanned, there is no need to scan before it.
Entering the birth height can save you a tremendous amount of time. The value does not have to be exactly the height of the first transaction but it must be before that transaction.
From Jul 2023 to Oct 2024, the Zcash blockchain received an excessively high number of large transactions. If your wallet was created after that period, you should enter a birth height after Oct 2024. It will save you hours or even days.