Windows 10: Microsoft Fixes Windows 11 KB5089549 Install Failures Caused by Limited EFI Partition Space

Microsoft has fixed the known issue that caused installation failures and 0x800f0922 errors when deploying the May 26, 2026, Windows 11 security update KB5089549.

The solution is included in the KB5089573 preview cumulative update released on May 26 and will be available to all users through the June Patch Tuesday updates later this month.

The failures were due to insufficient free space on the EFI System Partition (ESP), which led the update to roll back automatically on affected devices.

What Was Causing KB5089549 Install Failures and How to Fix Them


Microsoft confirmed two weeks ago that the problem affected devices with limited free space on the EFI System Partition, especially those with 10MB or less available. On these systems, the installation process would begin normally but fail during the reboot phase at around 35 to 36 percent completion.

Affected users saw a message stating, "Something didn't go as planned. Undoing changes," when the update rolled back. Logs from impacted systems included entries like "SpaceCheck" and "ServicingBootFiles failed," which pointed to insufficient free space on the EFI System Partition.

Microsoft says the issue has been fixed with updates released on May 26, 2026 (KB5089573) and later. Users who install these updates do not need to use any workaround.

To do so, open Settings, then Windows Update, go to Advanced options, and select Optional updates. From there, install KB5089573 or a later update. This will prevent the EFI partition install issue from occurring.

Microsoft recommends installing the latest update because it includes other improvements and fixes. The same resolution will be rolled out automatically to all users through the June Patch Tuesday cumulative update.

Mitigation Options If You Don’t Install the KB5089573 Optional Update


Users who choose not to install the May 2026 optional update can use Known Issue Rollback (KIR), a Windows feature that undoes problematic updates delivered through Windows Update. KIR is automatically applied to consumer and unmanaged devices.

In enterprise environments, administrators can manually address the issue by installing and configuring the Group Policy provided by Microsoft. Instructions for deploying the Known Issue Rollback group policies are available on Microsoft's support website.

The preview cumulative update KB5089573 for Windows 11 versions 24H2 and 25H2 was released on May 26. It includes 30 changes, such as the Low Latency Profile performance feature and various reliability improvements.

This update comes after a series of issues with Windows updates in 2026. Earlier this month, Microsoft confirmed that security updates released in April 2026 caused failures in third-party backup applications that relied on a vulnerable driver.

The company also fixed a Windows Autopatch bug that led to administrator-restricted driver updates being deployed on some devices managed by Autopatch in the European Union.

Thank you for being a Ghacks reader. The post Microsoft Fixes Windows 11 KB5089549 Install Failures Caused by Limited EFI Partition Space appeared first on gHacks.

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Installing Windows Vista/7 on a GUID Partition Table

Background

GUID Partition Table (GPT) is a boot sector technology poised to replace the venerable Master Boot Record (MBR) principally because MBR has a maximum capacity of 2 TB for a single partition (some single disks have reached 3 TB). Installing Windows on a GPT is a bit tricky because Windows wants to default back to MBR. In order to force Windows on to a GPT, we have to pre-format the drive prior to Windows installation. You can do that during Windows setup using the console.

Requirements

• Windows Vista or 7 (must be 64-bit no matter which OS is used)
• A motherboard with EFI BIOS
• A means to EFI boot the Windows setup (I had to use a USB DVD drive on MSI Z77A-G65, the internal SATA Bluray drives didn't have an EFI option)

Instructions

• Boot into Windows setup using EFI. On the MSI Z77A-G65, it showed up as UEFI:USB-ATAPI DVD ... This will change according to your motherboard and how you are attempting to enter setup. This step is critical. Without booting into setup via EFI, only MBR is available to the setup. There's no easy way to tell from within setup if it is running via EFI or not.
• Once you have booted into setup, continue through the process as you would normally until you reach the dialog which shows you the available drives. Load a driver, if necessary, then press SHIFT+F10 to open the command prompt.
• In the command prompt, enter the following lines, pressing enter after each one. Note that the <id> field below is the disk ID that you want to format as GPT from the "list disk" command. If there's only one drive, <id> will likely be 1. Note: All data on the drive will be lost during this process. Make sure to select the correct drive.
  • diskpart
  • list disk
  • select disk <id>
  • online disk
  • attributes disk clear readonly
  • clean
  • convert gpt
  • create partition efi size=102
  • create partition msr size=32
  • create partition primary
  • format fs=ntfs label="Operating System"
  • assign letter=C
  • exit
  "online disk" and "attributes disk clear readonly" are likely to fail. Don't worry, they are only precautionary. Change the drive letter and label to whatever you want. Also, the above command (specifically "create partition primary") will consume all remaining space on the drive. If you want multiple partitions with fixed sizes, substitute what you want in place of "create partition primary."
• You may now close the command prompt and click on "Refresh" back in the dialog to choose where to install Windows. You should now see at least 2 partitions (I think Microsoft Reserved is hidden) and it will only let you install on a non EFI/MSR partition. Click on the primary partition and proceed with the installation as normal.
• Note that in the EFI BIOS after installing Windows via EFI, you can no longer directly boot the volume Windows is installed on. Instead, you must boot via "Windows Boot Manager" (on MSI Z77A-G65, it was "UEFI: Windows Boot Manager"). Keep that in mind if you wish to tweak the boot order.

Conclusion

That should do it. You should be in Windows with >2 TB of hard drive capacity available if you had more than 2 TB on the Windows partition. Congratulations being on the bleeding edge of technology! *Rockout :rockout:

 

Installing Windows Vista/7 on a GUID Partition Table

Dear FordGT,

First of all, thank you very much for your very useful (and imho, most recommended) tip on installing Windows 7 on a GPT hard disk, which has enabled me to install Windows 7 Ultimate 64-bit on my brand-new Samsung Series 5 NP550P5C laptop (only a few weeks old, coming up to its one-month anniversary) which has an UEFI BIOS, after wiping its slow 1 Tb 5,400 rpm hard disk (will replace it with a SSD sometime in the future) clean of SamCrap bloatware and performing a clean Win7 install.

Now, I think I may have an interesting question for you.

I am thinking of assembling a mini-ITX pc with Intel quad-core i7-3770K and GTX660Ti 2 Gb sometime in the near future (when funds permit).

I am thinking of putting a 2 Tb 7,200 rpm hard disk and a 240 Gb SSD together, and using the SSD to cache the two 1 Tb partitions (after setting up the 102 Mb EFI system partition and the 32 Mb Microsoft Reserved partition and partitioning the remainder into two equal-size partitions of slightly under 1 Tb each) using Intel Smart Response Technology.

On the SSD, I intend to create the following partitions:- a 102 Mb partition to cache the EFI system partition, a 32 Mb partition to cache the Microsoft Reserved partition, a 64 Gb partition to cache the < 1 Tb drive C (coz Intel Smart Response Techology only allows a maximum of 64 Gb), another 64 Gb partition to cache the < 1 Tb drive D, a 16 Gb partition to copy the system RAM to SSD using Intel Rapid Start Technology when putting the computer to sleep (in S3/S4 mode) and the remaining 95/96 Gb partition (I have done the sums) as a normal hard disk for stuff that requires speedy access, for games like Sims 3 which requires a lot of disk accessing.

My question is this:-

Is what I am proposing above feasible or not ?

Would it be possible to use the partitions on the SSD and Intel Smart Response Technology to cache the EFI System partition and the Microsoft Reserved partitions ?

Would Intel Smart Response Technology be able to recognise both the EFI system partition and the Microsoft Reserved partitions, in addition to the two < 1 Tb partitions (drives C and D) ?

Thanks in advance.


TAG

 

Move EFI partition

its to enable win 10 to update to its anniversary edition.. it cant do this due to lack of C drive space i have had a quick try with the trial version of easus.. it didnt seem to be able to do what i want..

i am assuming i cant just delete the efi partition but maybe i could.. as yet i havnt even figured out how to get into the bios of the thing.. maybe that should be my next step.. *Smile

diskpart could probably do it but figuring out how (it aint that user friendly) might be difficult without step by step instructions..

trog