Signal
Windows 11 security update KB5089549 fails to install due to low EFI partition space
Evidence first: scan the strongest sources, then decide whether to go deeper.
Published 2026-05-18 08:33 UTCUpdated 2026-05-18 22:46 UTC
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Evidence trail (top sources)
top sources (3 domains)domains are deduped. counts indicate coverage, not truth.3 top sources shown
Overview
Microsoft's May 2026 Windows 11 security update KB5089549 encounters installation failures on devices with limited EFI System Partition space, typically 10 MB or less. The error manifests as 0x800f0922 or an "Undoing changes" message during reboot, preventing the update from completing and leaving systems exposed to security risks. Microsoft has confirmed the problem and provided interim workarounds, highlighting the importance of sufficient EFI partition space for patch deployment.
Score total
1.15
Momentum 24h
3
Evidence documents
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Independent publishers
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Independent origins
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Primary sources
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Secondary sources
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Source types
-
Duplicate ratio
0%
Why now
- The problem was identified with the May 2026 security update, impacting timely patching.
- Affected users may remain exposed until a fix is released, increasing risk.
- Awareness allows organizations to take interim measures to mitigate exposure.
Why it matters
- Failure to install security updates leaves Windows 11 systems vulnerable to exploits and cyberattacks.
- The issue affects devices with limited EFI partition space, a common configuration in some environments.
- Microsoft's acknowledgment and workaround advice are crucial for IT teams managing patch deployments.
LLM analysis
Topic mix: lowPromo risk: lowSource quality: medium
Recurring claims
- Windows 11 update KB5089549 fails to install due to insufficient free space on the EFI System Partition (ESP).
How sources frame it
- Microsoft: neutral
Consolidated multiple reports confirming the EFI partition space issue causing Windows 11 update failures.
All evidence
All evidence
Windows 11 update KB5089549 causes installation errors due to low EFI partition space
Scworld · scworld.com · 2026-05-18 22:46 UTC
Microsoft May security patch fails for some due to boot partition size glitch
Csoonline · csoonline.com · 2026-05-18 20:11 UTC
Microsoft confirms Windows 11 security update install issues
BleepingComputer · bleepingcomputer.com · 2026-05-18 08:33 UTC
Show filters & breakdown
Posts loaded: 0Publishers: 3Origin domains: 3Duplicates: -
Showing 3 / 3
Top publishers (this list)
- Scworld (1)
- Csoonline (1)
- BleepingComputer (1)
Top origin domains (this list)
- scworld.com (1)
- csoonline.com (1)
- bleepingcomputer.com (1)