Tracked Windows update
KB5120998 known issues and fixes
Windows 11 24H2/25H2 preview update associated with the tracked post-sign-in desktop failure.
- Release date
- Windows versions
- Windows 11 24H2, Windows 11 25H2
- OS builds
- 26200.9278, 26100.9278
- Official source
- KB5120998 — Microsoft Support
- Last verified
This is a directory of TraceCheck's tracked records, not a complete list of every vendor issue. Zero tracked records does not establish that an update is problem-free.
TraceCheck cross-reference
What role does this KB play?
Keep the update linked to the failure separate from the update linked to its resolution. These roles come from the cited issue records.
| Issue | This KB's role | Evidence |
|---|---|---|
| Windows black screen after KB5120998 on AVD / FSLogix | Originating update | Source: Microsoft |
An originating update identifies the documented association; it does not establish the technical root cause. A resolving update applies to its listed Windows versions. This historical index does not identify today's latest update.
Known issues
Mitigated Tracked software issue
Windows black screen after KB5120998 on AVD / FSLogix
Some Windows 11 devices fail to load the desktop after sign-in following KB5120998 or later updates. Microsoft primarily observed this on Azure Virtual Desktop hosts using FSLogix. Workarounds are documented; a full resolution remains pending in the reviewed vendor entry.
Windows 11 24H2 · KB5120998; Windows 11 25H2 · KB5120998; Windows 11 26H1; Windows 11 26H2
Resolved issues
No verified resolution records are currently linked.
Compatibility reports
No separate unconfirmed compatibility reports are currently tracked.
Related fixes and workarounds
Temporarily start Windows Explorer
FACT Official workaround · workaround
Open Task Manager with Ctrl+Shift+Esc, choose Run new task, enter explorer.exe and confirm. This starts the desktop session temporarily; it does not establish a permanent correction.
Workaround — permanent resolution not established
Applies to: Windows 11 24H2, Windows 11 25H2, Windows 11 26H1, Windows 11 26H2.
Risk: low (TraceCheck editorial assessment, not a vendor success rate)
Read Microsoft's instructions ↗Read Microsoft's instructions ↗
Administrator-managed KIR for Windows 11 24H2/25H2/26H2
FACT Official workaround · workaround
For managed Windows 11 24H2/25H2/26H2 devices, administrators can configure the version-specific KB5124010 260924_20021 Known Issue Rollback policy linked in Microsoft release health and restart. This temporarily disables the implicated change until a permanent resolution. The policy name is not a fixing cumulative update, and it must not be substituted for the 26H1 policy.
Workaround — permanent resolution not established
Applies to: Windows 11 24H2, Windows 11 25H2, Windows 11 26H2.
Risk: medium (TraceCheck editorial assessment, not a vendor success rate)
Read Microsoft's instructions ↗Read Microsoft's instructions ↗
Administrator-managed KIR for Windows 11 26H1
FACT Official workaround · workaround
For managed Windows 11 26H1 devices, Microsoft release health links the KB5124006 260924_20071 Known Issue Rollback policy. Administrators must install and configure the policy for this Windows version and restart the device. This temporarily disables the implicated change; a permanent correction remains pending. Do not use the distinct 24H2/25H2/26H2 policy as a substitute.
Workaround — permanent resolution not established
Applies to: Windows 11 26H1.
Risk: medium (TraceCheck editorial assessment, not a vendor success rate)
Evidence
- KB5120998 — Microsoft Support
Microsoft · Vendor documentation
Supports: Release date, supported Windows versions and OS builds.
Change history
No earlier verified state transitions are recorded.