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Quick answer

Moving supported data with Smart Switch is separate from activating cellular service. Samsung’s transfer guidance says to leave the SIM in the old phone until the transfer is complete. Open Smart Switch on the new Galaxy to receive data and on the old Android to send it, using a supported wireless or cable connection. A carrier activation screen does not mean you need to erase the old phone or transfer the number before copying files.

Choose the check that matches your symptom

Start with the row that describes what you see. You do not need to try every step.

Match your symptom to the relevant check
What you noticeWhere to start
SIM prompt appears before the transfer screenIdentify the activation stage
Both phones work and data needs copyingUse a supported local transfer
You need an independent copy before migrationConsider existing compatible external storage

Before you start

  • Use the exact model and platform described below. If a label or connection differs, stop and identify it before changing settings.
  • Keep passwords, verification codes, serial numbers and private documents out of any help request. Use synthetic or redacted details when describing an error.

Why this happens

A SIM provides cellular identity; it is not the container for all your photos, apps and messages. Setup can include both carrier activation and local migration, which are different tasks. Some app data, protected content and sign-ins require their own supported migration even when Smart Switch completes.

What to do, step by step

Try one step at a time. Stop when the issue is resolved. If an instruction doesn't match your device, use the official model-specific guidance instead.

1

Identify whether the prompt is transfer or activation

  1. Read the screen title on the new phone. Distinguish a carrier/SIM activation prompt from Smart Switch’s content-transfer screen.
  2. Keep both phones and the old SIM available. Do not remove an eSIM, cancel a plan or factory-reset the old phone to solve a migration prompt.
  3. If the setup wizard offers no supported way to proceed, ask Samsung or the carrier how to reach the transfer step for that exact model. Do not bypass ownership verification or assume every setup screen has Skip.
Smart Switch copies supported content; SIM or eSIM activation enables cellular service. A transfer can succeed while calls remain unavailable, so read which app or service is requesting the SIM.
2

Prepare both devices and preserve the originals

  1. Charge both phones; Samsung’s transfer guidance calls for at least 20% battery before starting. Update Smart Switch from a trusted store where needed.
  2. Check that the receiving device is a supported Galaxy phone or tablet and has enough available space for the selected content.
  3. Keep the old device unlocked when prompted, but enter its PIN or account credentials only on your own device. Have a separate backup of irreplaceable files before migration.
Keep the original phone and its data until the new device is checked. Both devices need adequate charge, and protected apps or authenticator accounts may require their own migration steps.
3

Start a local Android-to-Galaxy wireless transfer

  1. Open Smart Switch on the receiving Galaxy and choose Receive data. Select the Android/Galaxy source type and Wireless where those choices are shown.
  2. Open Smart Switch on the old Android and choose Send data, then its wireless option. Follow the on-device connection confirmations for these two phones.
  3. Select the content categories you need and choose Transfer when ready. Keep the devices together and do not interrupt the process to swap SIMs.
The old Android sends and the new Galaxy receives. Confirm that direction before choosing content; these controls are for Android-to-Galaxy transfer and do not describe an iCloud restore.
Smart Switch generated example showing old Android sending wirelessly and new Galaxy receiving.View larger
Original AI-generated UI example; not a captured screenshot. The highlighted controls match the described action; appearance and layout vary by model and software version.
4

Verify what arrived before changing service or erasing

  1. Read the completion summary on the receiving phone. Open a sample of photos, contacts and messages rather than assuming every app’s private data transferred.
  2. Sign in to apps through their own trusted screens and follow any app-specific migration requirements. Banking, authenticator and protected-content apps may need separate setup.
  3. Keep the old phone unchanged until important data and account access are checked. Then follow the carrier’s supported SIM/eSIM activation instructions as a separate task.
Open a sample of the transferred photos, contacts and messages instead of relying only on the completion screen. Keep the old device available for content or app sign-ins that did not move.
5

Use a separate external backup when it adds protection

  1. For a supported Galaxy with USB storage, connect a compatible USB flash drive or SSD to its charging/data port; an appropriate OTG adapter may be needed. Do not format a drive containing files you need.
  2. Open Smart Switch, select the SD card icon in the upper-right area, choose Back up, select the content and confirm Back up. Wait for Done before safely removing storage.
  3. To restore on a supported new Galaxy, attach that storage, open Smart Switch, select the SD card icon and Restore, choose the backup content and confirm Restore. Check the restored data and keep another independent copy.
A separate SSD backup adds another copy only if your Galaxy recognizes the connected storage. Confirm USB OTG, available power and filesystem support; never format a drive containing files you still need. External storage does not activate a SIM, unlock a protected phone or guarantee every app can be backed up.
Smart Switch example highlighting the storage icon and Back up on recognized USB storage.View larger
Original AI-generated UI example; not a captured screenshot. The highlighted controls match the described action; appearance and layout vary by model and software version.

Still not working? Know when to stop

Stop before deleting an eSIM, cancelling service, formatting a drive or erasing either phone. Use official ownership verification and carrier activation; no transfer tool can bypass a locked account or make an inactive line work.

Write down the exact model and error message before contacting official support.

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Useful tools, only if they fit your situation

Try the free checks first. Compare these optional products for the specific uses below; buying equipment does not guarantee a fix.

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    Kingston XS2000 portable SSD — 4TB, SXS2000/4000G

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    Consider only when: You need additional backup capacity and the actual Galaxy can power and recognize the drive; it is not needed just because no SIM is installed.

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Frequently asked questions

Must I move my SIM before Smart Switch?

Samsung recommends leaving it in the old phone until transfer is complete. Local data transfer and carrier activation are separate.

Does Smart Switch move my phone number?

It copies supported content. Your carrier controls SIM/eSIM activation and number service.

Can every app and password be copied?

No. Supported items depend on the source and app. Check important apps and account access individually before erasing the old device.

Can I use an SSD instead of direct transfer?

Samsung documents supported external USB/SSD storage for Smart Switch backup and restore. The phone must recognize the drive and have the required adapter, power and filesystem support.

Sources and editorial transparency

Documentation checked: 2026-11-13. Our instructions are written for this guide. Interface labels can change; this is a source review, not hands-on testing of every device.

Reference titles and source dates
  • Samsung — Transfer content with Smart Switch
  • Samsung — Wireless transfer and SIM timing
  • Samsung — External storage backup and restore

Prepared by TechTweety Editorial · Source-backed troubleshooting guide.