Microsoft Teams Auto-Answering calls when phone is connected to USB on PC to charge

Although disconnecting the usb from the PC to the phone initially seemed to resolve the auto-answering, it recurred shortly afterwards.

When the phone (an iPhone) is signed out of Teams, the auto-answering stops indicating a phone issue.

Since then, we have changed the following setting and it initially looks promising but (as we thought we had identified the cable as the cause which later reverted to auto-answering when not physically connected via a cable and thus did not resolve it)...

Setting changed which so far seems to resolve this (bold item)...

• Settings
• Apps
• Teams
  • Bluetooth (Off)
  • Local Network (Off)

Dear Pablo,

Thank you for sharing your question.

From your description, the issue seems to occur when your phone is connected to your PC via USB for charging, and incoming Microsoft Teams calls are automatically answered without any user interaction.

Please note that this forum is a user-to-user support community, so moderators do not have access to users’ accounts or device configurations. Based on the information you provided, I also attempted to reproduce the behavior on my side but was unable to replicate the issue.

To help narrow down the possible cause, you may try the following checks:

Check whether you are signed in to the same Teams account on your PC

If your Teams account is signed in on both your mobile device and PC, the call might be picked up by another active session without you noticing.

If this is the case, please try signing out of Teams on your PC and then place a test call to see whether the issue still occurs.

Follow the instruction in this article to sign out Teams: Sign out or remove an account from Microsoft Teams - Microsoft Support

Change the USB connection mode on your phone

When connecting your phone to a PC via USB, devices sometimes allow different connection modes such as file transfer, media transfer, or charging only.

Try switching to another connection mode instead of the default charging mode. This can help determine whether the behavior is related to how the device is communicating with the PC through the USB connection.

The steps to change the USB connection mode may vary depending on the phone model you are using. If you are unsure how to do this, please share your phone model and the operating system of your PC so I can provide more specific guidance.

Try charging the phone using a wall charger instead of your PC

Please try charging your phone using a standard wall charger rather than connecting it to the PC. If the issue does not occur in that scenario, it may indicate that the behavior is related to a conflict or interaction between the phone and the PC through the USB connection.

To further investigate the issue, please feel free to share additional details such as:

• Your devices model and operating system version
• Whether the call appears to be answered on the PC or the mobile device
• Whether the issue occurs every time the phone is connected to the PC

Providing these details will enable us to offer the most accurate next steps and, if necessary, route your request to the appropriate team for further assistance. Looking forward to your response so we can assist you further!

If you have extra questions about this answer, please click "Comment".  

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Teams itself does not provide an auto‑answer setting for USB‑connected phones; the behavior is driven by the connected device and its integration with Teams.

To prevent auto‑answering when the phone is connected via USB:

1. Use a Teams‑certified device or configuration
   • Certified devices are designed to support standard call control actions (answer, mute, volume, hold, etc.) without unexpected behavior.
   • Non‑certified or legacy devices (including some older Skype for Business/Lync‑era hardware) may not behave correctly with Teams and can cause issues such as unintended call control.
   • For optimum performance and predictable call behavior, use a device that is explicitly “Certified for Microsoft Teams.”
2. Avoid or disable conflicting third‑party device software
   • Device vendor utilities (for example, headset/phone management apps) can add communication features that interfere with Teams call control.
   • If a device is auto‑answering calls when plugged in, close or uninstall any vendor control software as a first troubleshooting step, then test Teams calls again.
3. Prefer supported personal peripherals instead of phone‑as‑device
   • Teams supports USB headsets, speakers, and other certified peripherals for call control (answer, mute, volume, etc.).
   • Using a mobile phone as a USB device for charging or call control is not part of the supported Teams call‑control model described for certified devices, and can lead to unpredictable behavior.
4. Replace or reconfigure legacy/unsupported hardware
   • Older or non‑certified devices may not receive updates to correct issues with Teams.
   • If the auto‑answer behavior is tied to such a device, replacing it with a Teams‑certified model is the recommended fix.

If the issue persists after removing third‑party software and avoiding non‑certified/legacy devices, configure Teams calls to use a different audio device (a certified headset or speaker) so that connecting the phone over USB no longer affects call control.

References:

• Use certified devices to help manage calls and meetings in Microsoft Teams