> ## Documentation Index
> Fetch the complete documentation index at: https://elephas.app/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Add Another Computer to Personal Sync

> Add a second Mac or Windows PC to Elephas Personal Sync. Sign in, compare five words on both screens, approve the new computer and let it download your Brains.

To add a computer to Personal Sync, start on the new computer, then approve it from a computer that already syncs. Both screens show five words. You approve only if all five match.

<Info>
  Personal Sync is part of the Professional plan, which works on up to 3 devices. See [Device limits](/docs/plans-and-billing/device-limits).
</Info>

## Before you start

* Sync must already be on, on at least one computer. If not, [turn on Sync](/docs/sync-and-devices/turn-on-sync) there first.
* Install Elephas on the new computer: [Mac](/docs/getting-started/install-elephas-on-mac) or [Windows](/docs/getting-started/install-elephas-on-windows). Let it finish its [first-run downloads](/docs/getting-started/first-run-downloads). The new computer needs its search model to index what arrives.
* Sign in on the new computer with **the same Elephas account**, in **Settings › Plan & Billing**.
* Have both computers in front of you, both online. A request that is not approved expires after about 30 minutes.

## Steps

<Steps>
  <Step title="On the new computer, open Settings › Sync">
    On Mac, choose **Elephas › Settings…** or press **⌘,**. On Windows, choose **File › Settings…** or press **Ctrl+,**. Then choose **Sync**.
  </Step>

  <Step title="Choose I already use Sync on another device">
    Select **I already use Sync on another device**. Check the name next to **This computer:** and click **Rename** if you want a clearer one, such as "Office PC". Tick **I understand there is no recovery**.
  </Step>

  <Step title="Click Join from My Other Device">
    The new computer shows: "Waiting for approval. On your other device, open Settings → Sync and compare these words:" followed by five words. Leave this screen open.
  </Step>

  <Step title="On a computer that already syncs, open Settings › Sync">
    Elephas shows a notification, **New device wants access**. Open **Settings › Sync**. In **Devices**, the new computer shows **Waiting for your approval** and a **Review** button. Click **Review**.
  </Step>

  <Step title="Compare the five words">
    The **Approve New Device** card shows the new computer's name and platform, and five words: "Compare these five words with the words shown on the new device. Approve ONLY if they match exactly."

    Read them against the words on the new computer, in order.
  </Step>

  <Step title="Approve only if they match">
    If every word matches, click the approve button (**The words match**). If any word differs, click the reject button (**They don't match**).
  </Step>

  <Step title="Wait for the new computer to catch up">
    The new computer shows **Receiving keys**, then "This device is now syncing." It downloads your Brains, documents and chats, and the status reads **Indexing synced documents** while it indexes them locally.
  </Step>
</Steps>

## How it works

### Why five words

The five words are calculated separately on each computer from the details of this one request. If they match, the two computers are talking directly to each other, and nobody in between, including the sync server, swapped in a different device. If they don't match, the request did not come from the computer you are holding. Rejecting it costs nothing; you can start again.

### What the new computer receives

Approval sends the new computer the encryption keys for your Brains and chats, wrapped so only it can open them. It then receives your full synced history, not only changes made from now on.

### What the new computer builds itself

Search indexes never sync. The new computer indexes your documents itself, on the device. A large library takes a while; you can use Elephas meanwhile, and documents become searchable as they finish.

### Your other computers are told

Every approval, rejection and removal is recorded in **Security History** in **Settings › Sync** on each synced computer. These records never include document names or content.

## Troubleshooting

<AccordionGroup>
  <Accordion title="The words don't match">
    Reject on the existing computer, then start again on the new one. If they still don't match, do not approve. [Contact support](/docs/troubleshooting/contact-support).
  </Accordion>

  <Accordion title="The enrollment expired">
    The new computer says "The enrollment expired. Start again." Click **Join from My Other Device** again and approve within the time limit.
  </Accordion>

  <Accordion title="The new computer can't get a place on my account">
    Professional works on up to 3 devices, and each synced computer takes one. Remove a computer you no longer use from **Settings › Sync** on a synced computer. See [Remove a device](/docs/sync-and-devices/remove-a-device) and [Sync troubleshooting](/docs/troubleshooting/sync-troubleshooting).
  </Accordion>
</AccordionGroup>

## Related articles

<CardGroup cols={2}>
  <Card title="Sync encryption" href="/docs/privacy-and-security/sync-encryption" />

  <Card title="What syncs" href="/docs/sync-and-devices/what-syncs" />

  <Card title="Remove a device" href="/docs/sync-and-devices/remove-a-device" />

  <Card title="Move to a new computer" href="/docs/sync-and-devices/move-to-a-new-computer" />
</CardGroup>


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