Windows 10 users may want to hold off on updating their PCs: The first cumulative patch for the Windows 10 April 2018 update is causing some PCs to enter a cycle of failed boots.

The bug in update KB4103721 was first reported by Microsoft forum users, only some of whom were affected. Microsoft added a note to the KB4103721 patch notes stating “select devices with Intel SSD 600p Series or Intel SSD Pro 6000p Series may repeatedly enter a UEFI screen after restart or stop working.”

Forum users have suggested a number of different causes as well, and Microsoft hasn’t issued any additional statements regarding the bug.

SEE: Windows 10 spotlight: Prepare, repair, and recover (Tech Pro Research)

KB4103721 was designed to fix a number of issues that have arisen in the April 2018 update, but inadvertently caused a much more serious one. If you have a Windows 10 PC running the April 2018 update you should hold off installing this latest patch until Microsoft issues definite word that it has been fixed.

How to fix a Windows 10 PC affected by KB4103721

In both the Microsoft forum thread and the KB4103721 patch notes only one solution has been found to work: rolling back to an earlier version of Windows 10, as demonstrated on Windows Latest. Luckily for those affected, Windows creates a restore point before an update is installed, so if you can get to the Advanced Startup Options (ASO) screen you should be able to fix it.

  1. Reboot your computer and hit F11 as soon as it powers up–if you see the Windows boot logo you’ve missed your chance and will need to restart again. If you do it correctly you should be on the ASO screen. Note: F11 is the default key, but some manufacturers change this setting. If F11 doesn’t work check your PC maker’s website.
  2. On the ASO screen click on Advanced Options.
  3. Under Advanced Options click on Go Back To Previous Build.
  4. Windows should reboot, roll back, and start normally.

If you don’t have a valid system restore point you’re not out of luck–it’s just going to take a few extra steps to solve the problem since you’ll have to manually delete the update in Safe Mode.

  1. Start by booting into ASO. Once there, navigate to Troubleshoot > Advanced Options > Startup > Restart.
  2. When your PC reboots you’ll have access to several boot modes, including Safe Mode and Safe Mode With Networking, either one of which will be fine for this purpose.
  3. Choose your option, boot into Safe Mode, and log in with your Windows credentials. Note: you’ll need to be an admin in order to roll back an update.
  4. Once in Safe Mode, open the Settings app. From there go to Update & Security > Windows Update > View Update History > Uninstall Updates.
  5. On the Uninstall Updates screen find KB4103721 and uninstall it.
  6. Restart your computer and boot into Windows 10 normally. It should work fine.

If neither of those options works you may have to do a clean installation of Windows 10. It probably won’t come to that, but it’s best to hold off on that update just in case.

The big takeaways for tech leaders:

  • A bug in the latest Windows 10 cumulative update (KB4103721) is rendering some PCs unable to boot. Microsoft reports the bug is affecting those with certain Intel SSDs.
  • Windows users are advised to wait to install the update until Microsoft has fixed it. Those affected should be able to fix their computers using a restore point or by manually deleting the update from the Windows 10 Settings app.

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