Key changes and cautions
This is an optional preview rather than an urgent security fix; stability-focused systems can wait for the next regular cumulative update.
Microsoft · Windows 11 선택적 업데이트
KB5120998 — is it safe to install?
Windows 11 24H2·25H2 KB5120998 미리 보기 · 2026-08-27
What is this update?
An optional Windows 11 preview update that delivers non-security quality improvements before the next regular cumulative update.
Watch58/100
I wouldn't update.
This is an optional preview rather than an urgent security fix; stability-focused systems can wait for the next regular cumulative update. Check official applicability and whether a later release supersedes it before installation.
QUICK ANSWER
I wouldn't update.
This is an optional preview rather than an urgent security fix; stability-focused systems can wait for the next regular cumulative update. Check official applicability and whether a later release supersedes it before installation.
New features, security and compatibility
Problems fixed
No separately reviewed item is available for this section yet.
Known issues that remain
No separately reviewed item is available for this section yet.
Officially confirmed issues
Key changes and cautions
This is an optional preview rather than an urgent security fix; stability-focused systems can wait for the next regular cumulative update.
Community-reported issues
No repeating community signal is currently linked to this update.
Public Reddit/forum/support-community reports are grouped as early-warning signals and kept separate from official issues.
If something broke after updating
When Windows will not boot after an update
Start with the lowest-risk Windows recovery options when a black screen or restart loop begins after an update.
1. Open Windows Recovery Environment
If Windows does not boot normally, open recovery options. A BitLocker recovery key may be required.
2. Uninstall the latest quality update
If the problem began immediately after updating, consider removing the latest quality update after confirming backups.
When a Windows update repeatedly fails to install
Begin with restart and built-in troubleshooting; use a repair reinstall only as a later official step.
1. Restart and check Windows Update again
Complete any pending restart and retry from Windows Update while recording a repeated error code.
2. Consider reinstalling the current Windows version
If basic troubleshooting fails, review Microsoft’s current-version reinstall procedure after confirming power and backups.
Before you install
Before installing
Back up important files, keep Windows recovery options available, and recheck official applicability and known issues.
User reports
Field reports 0 · stable installs not enough data · confidence 낮음
Did you install this update?
Your result helps build Updatehey’s independent field dataset.
Related searches
KB5120998 Windows 11 24H2 25H2 preview issues optional update
Related recovery guides
Pause Windows updates · Uninstall a problematic update · Repair Windows Update
Evidence freshness
Official evidence has been checked recently by the automated source monitor.
Frequently asked questions
Is KB5120998 safe to install?
I wouldn't update.. This is an optional preview rather than an urgent security fix; stability-focused systems can wait for the next regular cumulative update. Check official applicability and whether a later release supersedes it before installation.
Are there known issues with KB5120998?
Key changes and cautions. This is an optional preview rather than an urgent security fix; stability-focused systems can wait for the next regular cumulative update.
What should I do before or after installing KB5120998?
Before installing. Back up important files, keep Windows recovery options available, and recheck official applicability and known issues.
Related updates
- KB5121003 · I'd update. 2026-08-11
- KB5121000 · I'd update. 2026-08-11
- KB5101684 · I wouldn't update. 2026-07-28
- KB5121767 · I'd wait for now. 2026-07-18
Evidence timeline
Recent official-document changes and community signals linked to this update. Official and unofficial evidence remain separated.
Official source changes
- 2026-08-31 20:17:55 · Windows 11 24H2 릴리스 상태
정규화된 본문 변경은 있으나 주요 문장 차이는 작음 · View original - 2026-08-31 20:17:55 · Windows 11 25H2 릴리스 상태
정규화된 본문 변경은 있으나 주요 문장 차이는 작음 · View original - 2026-08-30 02:38:40 · Windows 11 25H2 릴리스 상태 · View original
- 2026-08-29 00:17:24 · Windows 11 24H2 릴리스 상태
추가 1개 · 삭제 1개 문장/블록 · View original
Update information changes as vendors publish new evidence. Back up important systems before installing.