Windows 11 KB5089549 Slow Startup and Login Screen Delay May 2026

What is the KB5089549 Slow Startup and Login Screen Delay?

KB5089549 is the Windows 11 cumulative update released on Patch Tuesday, May 13, 2026 for versions 24H2 and 25H2. Microsoft officially acknowledged on May 13, 2026 that affected machines experience a 45 to 120 second hang at the spinning-dots screen after the BIOS hand-off, followed by a black login screen that takes another 30–90 seconds to render the user tile. The total boot time can balloon from a normal 15 seconds to over 3 minutes on otherwise healthy hardware.

The root cause Microsoft confirmed is the same one that triggers install error 0x800f0922 in the same rollup: the EFI System Partition (ESP) lacks the free space the new bootloader requires. When the bootloader cannot stage its runtime configuration, the boot sequence falls back to a serialized recovery path that retries each component instead of loading them in parallel — producing the long delay.

When does it occur?

• Immediately after KB5089549 finishes installing and the machine reboots for the first time
• On every cold boot following the May 2026 patch (warm reboots are slightly faster)
• On systems whose ESP is smaller than 100 MB (PCs imaged on Windows 10 or earlier 11 builds)
• On dual-boot machines sharing the ESP with GRUB, rEFInd, or Clover
• After upgrading from 23H2 to 24H2 in-place where the ESP was never resized
• On OEM laptops (Dell, HP, Lenovo) that stored WinRE inside the ESP

Common causes

• ESP has less than 10 MB free after KB5089549 stages its new bootloader components
• Orphaned bootmgfw.efi.bak and BCD.LOG files from prior cumulative updates
• Stale font and language files in \EFI\Microsoft\Boot\Fonts\
• Third-party bootloader entries left over from removed Linux installs
• Corrupt BCD store forcing serialized component initialization
• Group Policy delaying logon scripts (SyncForegroundPolicy waiting on the network stack)
• Fast Startup feature interacting badly with the new bootloader's hibernation hand-off
• Credential Guard or VBS re-initializing on every cold boot after the patch

Step-by-step fixes

1. Confirm the delay is KB5089549-related. Open an elevated PowerShell and run Get-WinEvent -LogName "Microsoft-Windows-Diagnostics-Performance/Operational" -MaxEvents 20 | Where-Object {$_.Id -eq 100}. Look for BootTime values above 60000 ms that began on or after May 13, 2026.

1. Check ESP free space — the most common root cause. In an elevated PowerShell:

   mountvol S: /S
   Get-PSDrive S | Select-Object Used,Free

If Free is below 10 MB, this is your problem.

1. Clear stale ESP files (safe — Windows regenerates them on next boot):

   Remove-Item "S:\EFI\Microsoft\Boot\Fonts\*.ttf" -Force
   Remove-Item "S:\EFI\Microsoft\Boot\*.bak" -Force
   Remove-Item "S:\EFI\Microsoft\Boot\BCD.LOG*" -Force
   mountvol S: /D

1. Apply Microsoft's Known Issue Rollback (KIR). On Pro/Enterprise, download KB5089549-BootDelay-KIR.msi from the Microsoft Update Catalog and import it via gpedit.msc → Computer Configuration → Administrative Templates → Microsoft KIR → "KIR for KB5089549 boot delay." Set to Enabled and reboot. Home edition systems receive the KIR automatically within 72 hours of the May 16, 2026 server-side push — no action needed.

1. Disable Fast Startup to bypass the broken hibernation hand-off. Control Panel → Power Options → "Choose what the power buttons do" → "Change settings that are currently unavailable" → uncheck "Turn on fast startup." Save changes and reboot.

1. Rebuild the BCD store if it became corrupt. Boot to Windows Recovery (hold Shift while clicking Restart → Troubleshoot → Advanced options → Command Prompt) and run:

   bootrec /fixmbr
   bootrec /fixboot
   bootrec /scanos
   bootrec /rebuildbcd

1. Suppress the network wait on logon if Group Policy is delaying the login screen. In gpedit.msc → Computer Configuration → Administrative Templates → System → Logon → set "Always wait for the network at computer startup and logon" to Disabled. Reboot.

1. Uninstall KB5089549 as a last resort. From elevated PowerShell: wusa /uninstall /kb:5089549 /quiet /norestart then reboot. Pause updates for 7 days in Settings → Windows Update → Pause for 1 week to let Microsoft push the server-side fix before the patch returns.

If it still doesn't work

If the delay persists after applying the KIR and freeing ESP space, the issue is likely a corrupt servicing stack. Run sfc /scannow followed by DISM /Online /Cleanup-Image /RestoreHealth from an elevated prompt, then reboot twice — the first reboot reseals the bootloader, the second confirms the fix. If DISM reports an unrecoverable error, perform an in-place upgrade using the latest Windows 11 ISO (download from Microsoft, mount, run setup.exe) which rebuilds the boot configuration without losing apps or files. For machines that boot to a black screen with only a cursor for 5+ minutes, check the Microsoft Q&A thread tracking KB5089549 and confirm your winver build is 26100.4751 (24H2) or 26200.2310 (25H2) — earlier preview builds had a separate, unrelated regression.