Microsoft pushed out the Windows 10 update KB3081424 last week. It is a cumulative update for Windows 10 that contains fixes released previously and new fixes.
The Microsoft Knowledge Base article does not reveal the features that got patched, only the files that change when the update is installed on Windows 10 machines.
While the update did install fine on most machines, a small number of users ran into reboot issue during installation.
Most users describe that their computer goes in a vicious cycle of attempts to install the update, reboots during that process, rollbacks, and more reboots.
The process repeats after the rollback as Windows picks up the update again and since updates are installed automatically by default -- they are mandatory on Home systems while they can be delayed on Pro systems -- the cycle begins anew.
Microsoft's tool to block updates on Windows 10 may be a solution but at least some users reported that the tool is not working properly in this case.
While Windows 10 Pro users may delay the update for the time being by not installing it, Home users have no such option.
Microsoft removed update management options in Windows 10 that were available in previous versions of the operating system.
A solution for fixing the failed update was posted on Microsoft's Answers forum. The issue is caused by invalid user SID entries in the Windows Registry.
Note: The fix posted below requires editing of the Windows Registry. It is recommended that you create a System Restore point or other type of backup before you make changes to the Windows Registry.
- Tap on the Windows-key, type regedit and hit enter.
- Confirm the UAC prompt that comes up.
- Navigate to the key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList
- There you find listed all user profiles that exist on the machine.
- The entries S-1-5-18, S-1-5-19 and S-1-5-20 are used by the system and need to be left alone.
- If you have more than one S-1-5-21* entry, you may be able to fix the issue.
- All that is left is to click on each of the profiles starting with S-1-5-21 to link it to a user account on the system. You may do so by looking at the profileimagepath value after selecting the account.
- If you spot an account that is no longer valid, delete its keys.
- Restart the computer.
KB3081424 is the second Windows 10 update (KB3074681 is the first) that is causing issues on some machines either during or after installation. While that happened in the past as well on previous versions of Windows, the forced nature of updates makes it much harder for users and administrators to block and fix these issues. (via Wayne Williams, Betanews)