Sign in with Microsoft
Sign in or create an account.
Select a different account.
You have multiple accounts
Choose the account you want to sign in with.

This article applies to Surface 3 LTE devices only. If you have a non-LTE Surface 3 device, this article doesn't apply to you.


When you wake a Surface 3 LTE device that has the January 19, 2016, system firmware update installed, you may notice the following problems:

  • The Surface 3 LTE device doesn't connect to a wireless network.

  • Wi-Fi and LTE/Cellular connectivity options are missing in Windows.

  • Bluetooth doesn't work.

  • Device Manager shows an error on the Marvell AVASTAR Wireless-AC Network Controller and Surface 3 modem devices.

Note These problems occur only when you wake the device from hibernation.


These problems are caused by a race condition in the Surface CoSAR driver. This driver is included in the "System Firmware Update - 1/19/2016" update for Surface 3 LTE devices.

Note Only Surface 3 LTE devices use the Surface CoSAR driver.


To work around these problems, restart Windows. However, the problems may continue to occur until you install the hotfix that's provided in the "Resolution" section.


A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that's described in this article. Apply this hotfix only to systems that are experiencing this specific problem.

If the hotfix is available for download, there's a "Hotfix Download Available" section at the top of this Knowledge Base article. If this section does not appear, submit a request to Microsoft Customer Service and Support to get the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that don't qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, go to the following Microsoft website: The "Hotfix Download Available" form displays the languages for which the hotfix is available. If you don't see your language, it's because a hotfix isn't available for that language.

Installation instructions

  1. Download the hotfix that is provided in this article.

    Note You may receive a signature error when you download the hotfix. However, you can run the file later from the "Downloads" folder (or whichever folder you downloaded the file to).

  2. Run the hotfix .exe file that you downloaded.

  3. Select a folder in which to extract the hotfix files.

  4. Locate the folder to which you extracted the files.

  5. Open the SurfaceCoSARDriver subfolder.

  6. Right-click the SurfaceCoSARDriver.inf file, and then click Install.

  7. When you're prompted, click Yes to install the file.

  8. After the installation is complete, restart Windows.

Need more help?

Want more options?

Explore subscription benefits, browse training courses, learn how to secure your device, and more.

Communities help you ask and answer questions, give feedback, and hear from experts with rich knowledge.

Was this information helpful?

What affected your experience?
By pressing submit, your feedback will be used to improve Microsoft products and services. Your IT admin will be able to collect this data. Privacy Statement.

Thank you for your feedback!