"Microsoft has received a small number of reports of Windows 10 freezing after installing the Anniversary Update on systems with the operating system stored on a solid-state drive (SSD) and apps and data stored on a separate drive. This issue does not occur when starting Windows 10 in Safe Mode," Microsoft said on its support forum.
Microsoft is likely to roll-out a fix as part of a software update eventually, but until it's completed its investigation, it has provided steps to overcome the freezing issue.
If it's been less than 10 days since they've installed the Anniversary Update, affected users can sign into Windows 10 using Safe Mode and move apps and data to the same drive as the operating system. From there, they can revert to the previous version of Windows 10.
If it's been more than 10 days since installation and users are unable to sign in to Windows, there are two methods to roll back to the previous build. These methods involve using the Recovery Console or alternatively the Settings app from Safe Mode.
Once users arrive at the sign-in screen, they should hold the Shift key down while selecting Power and Restart. From there, users should be able to move back to the previous build by selecting Troubleshooting and Advanced Options.
Microsoft says it will update the post with more details once it's completed its investigation. In the mean time, affected Windows 10 users who would like to work with Microsoft's support team can express their interest by replying to the post.