bleepingcomputer[.]com/news/microsoft/windows-10-kb5075039-update-fixes-broken-recovery-environment/
support.microsoft[.]com/en-us/topic/kb5075039-windows-recovery-environment-update-for-windows-10-version-21h2-and-22h2-march-3-2026-aac888cb-fd3e-4bc0-9ef6-eabd32d4039e
The last full update to Win10, before the new security-only updates started, may have broken the WinRE recovery environment. Stored on the usually last, usually hidden disk partition, it gives you a limited recovery environment somewhat similar to the same feature on Win7 installation DVDs. Microsoft acknowledged the problem in February, 2026, and has now released a fix, KB5075039. To receive the update the copy of Win10 must meet 3 requirements and you have to click the Check For Update button. The requirements are 1) the recovery environment has to be enabled, the recovery environment version has to be earlier than 10.0.19041.6807, and the recovery partition must have 250MB of free space. To see if the recovery environment is enabled, use the command reagentc /info using the Command Prompt running as admin. Determining the recovery partition free space is probably easiest using AOMEI Partition Assistant to view the partition's properties if you have it installed. You can also run the PowerShell command Get-Partition | Get-Volume, running PowerShell as admin, but it might be difficult figuring out which partition is the recovery partition. To find the recovery environment version number I *think* the easiest way might be to use Event Viewer, then got to Windows Logs -> System, & Find [under the Action menu} WinREAgent. Double click the found entry and it should show the version. I say I *think* because this works in Win11 -- my Win10 VMs have the recovery environment disabled.
On their page for this update [linked above] Microsoft includes links to ways to increase the recovery partition size, but personally I'd advise a good deal of caution. To increase the recovery partition's size, some other partition, usually the one with Windows on it, has to shrink. Then the recovery partition has to move over to include that new free space. Do a disk image backup first, that you know you can restore, because while it's rare, shrinking & moving partitions can lose everything on the disk. And bear in mind, the recovery environment is a finicky beast. Even if you do everything 100% perfectly, in my experience Windows may refuse to enable the recovery partition/environment afterward.