user12023: This is very closely related to Import wallet.dat into a new Bitcoin-Qt client, but I feel this is not a duplicate because the (great) answer to that Q is for only restoring one wallet.
I used Bitcoin-QT about a year back and had two separate wallets within it.  I have these backed up as two separate wallet.dat files.  After some computer wipe, I now need to restore the two wallets into the one Bitcoin-QT client.
Using the prior Q, I have been able to import one of the wallets back into the Bitcoin-Qt client.  I now need to bring the other one in.
How can I import a second backup into my existing account, without the need of sending my first wallets amount to a separate external wallet?

user3697: There is (yet) no multi wallet support in bitcoin-core.
You can try to stop Bitcoin-Qt, replace your wallet.dat (rename the old one, place the new one) and start Bitcoin-Qt. If your wallet is really old, it will perform a rescan for new transactions and this can take some minutes.
To merge your wallets:

Open Console and enter dumpwallet <filename>
Stop Bitcoin-Qt
Replace wallet.dat with your new wallet file (move the current wallet.dat file to a save place)
Start Bitcoin-Qt
Open Console and enter importwallet <filename>.


12023: <p>This is very closely related to <a href="https://bitcoin.stackexchange.com/questions/10974/import-wallet-dat-into-a-new-bitcoin-qt-client">Import wallet.dat into a new Bitcoin-Qt client</a>, but I feel this is not a duplicate because the (great) answer to that Q is for only restoring one wallet.</p>

<p>I used Bitcoin-QT about a year back and had two separate wallets within it.  I have these backed up as two separate wallet.dat files.  After some computer wipe, I now need to restore the two wallets into the one Bitcoin-QT client.</p>

<p>Using the prior Q, I have been able to import one of the wallets back into the Bitcoin-Qt client.  I now need to bring the other one in.</p>

<p>How can I import a second backup into my existing account, without the need of sending my first wallets amount to a separate external wallet?</p>
 3697: <p>There is (yet) no multi wallet support in bitcoin-core.</p>

<p>You can try to stop Bitcoin-Qt, replace your wallet.dat (rename the old one, place the new one) and start Bitcoin-Qt. If your wallet is really old, it will perform a rescan for new transactions and this can take some minutes.</p>

<p>To merge your wallets:</p>

<ul>
<li>Open Console and enter <code>dumpwallet &lt;filename&gt;</code></li>
<li>Stop Bitcoin-Qt</li>
<li>Replace wallet.dat with your new wallet file (move the current wallet.dat file to a save place)</li>
<li>Start Bitcoin-Qt</li>
<li>Open Console and enter <code>importwallet &lt;filename&gt;</code>.</li>
</ul>
