Microsoft has acknowledged a potential hiccup with its upcoming May 2026 security update, which may fail to install properly, presenting users with the message: “Something didn’t go as planned. Undoing changes.” This issue stems from the EFI System Partition (ESP), the critical area from which devices typically boot. The ESP’s minimum required size is 200 MB, and it is managed by the operating system. However, if the available space dips below 10 MB, users may encounter a 0x800f0922 error code, leading to installation failures during the reboot phase, particularly around the 35-36% mark.
As with any security update, this one contains essential patches that need to be implemented. In previous discussions, we referred to this update as a “doozy of a Patch Tuesday.” While there have been no reports of active exploitation, the update addresses numerous critical Microsoft CVEs, underscoring its importance.
For those affected by this installation issue, Microsoft has proposed two potential solutions: a registry edit—which may elicit groans from administrators—or a Known Issue Rollback (KIR). The company noted, “The resolution has already propagated automatically to consumer devices and non-managed business devices.”
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This complication impacts Windows 11 versions 25H2 and 24H2, surfacing at a time when Microsoft had been enjoying a relatively smooth operation with its software products. The timing of this announcement is particularly unfortunate, coinciding with a blog post titled “Improving Windows Quality.” It appears that Microsoft still has considerable work ahead to enhance the quality of its offerings. Transitioning a vast operating system like Windows is akin to steering a supertanker—changing course is a gradual process.
As administrators prepare to implement the KIR group policy to mitigate this latest challenge, it’s understandable that many might reflect on Microsoft’s ongoing quality assurances with a sense of skepticism, echoing the age-old adage: “The more things change, the more they stay the same.”®
