Microsoft published a new Windows 11 preview cumulative update on June 23, 2026. The main update is KB5095093 for Windows 11 versions 25H2 and 24H2, moving systems to OS builds 26200.8737 and 26100.8737. Microsoft also published KB5095091 for Windows 11 version 26H1, build 28000.2340.
This is important, but it is not a new Patch Tuesday emergency. Microsoft labels KB5095093 and KB5095091 as preview updates and says they include quality improvements. For most regular home users, that means this update is optional today. For businesses, IT departments, and anyone who likes to know what is coming before the next monthly security release, it is worth paying attention because many preview-update changes often roll forward into the next security update.
Apple’s official security releases page did not list a new same-day macOS security update or Rapid Security Response for June 23, 2026 at the time of this check. The latest macOS security entries shown by Apple were still macOS Tahoe 26.5.1 on June 1, 2026 and the May 2026 macOS security updates.
In This Article
Quick Summary
- Windows 11 24H2 and 25H2: Microsoft released KB5095093 on June 23, 2026 as a preview cumulative update.
- Windows 11 26H1: Microsoft released KB5095091 on the same date for version 26H1 devices.
- Security status: Microsoft describes these as non-security/preview quality updates, not a new zero-day or emergency security release.
- Business impact: IT teams should review the changes now because preview fixes and feature behavior may show up more broadly in the next security update.
- Apple/macOS: No new same-day macOS security release was listed on Apple’s official security releases page at the time of publication.
What Microsoft Released Today
| Update | Applies to | Build after install | Plain-English note |
|---|---|---|---|
| KB5095093 | Windows 11 version 25H2 and Windows 11 version 24H2 | 26200.8737 and 26100.8737 | Preview cumulative update with production-quality improvements, Windows Secure Boot certificate messaging, feature rollouts, and several reliability fixes. |
| KB5095091 | Windows 11 version 26H1 | 28000.2340 | Preview cumulative update for newer 26H1 systems, with many similar quality and reliability improvements. |
The update history page for Windows 11 now lists KB5095093 under both Windows 11 version 25H2 and Windows 11 version 24H2. Microsoft’s KB page says the update applies to all editions of those versions.
What Changed In KB5095093
The most important customer-facing point is that KB5095093 is a preview update. Preview updates let Microsoft ship non-security fixes and new behavior before the next regular security release. They are useful for testing, troubleshooting, and getting ahead of changes, but they are not something every business has to rush onto every workstation tonight.
Secure Boot certificate messaging continues
Microsoft again highlights Windows Secure Boot certificate expiration. Microsoft says Secure Boot certificates used by most Windows devices are set to expire starting in June 2026. The same notice says devices that have not yet received newer certificates should continue to start and operate normally, and standard Windows updates should continue to install.
For customers, the practical takeaway is not panic. It is inventory and update hygiene. Devices that stay current through Windows Update are more likely to receive the certificate maintenance Microsoft is delivering over time. Businesses that block Windows Update, build custom images, use unusual boot configurations, or keep old deployment media around should pay closer attention.
Optional update behavior matters
Microsoft says KB5095093 is available through Windows Update as an optional update. On a normal Windows 11 PC, that means users generally need to go to Settings > Windows Update > Advanced options > Optional updates and choose it. Microsoft also notes that these changes will appear in the next security update for Windows Update for Business.
That is a big distinction for small businesses. If your computers are managed with Windows Update for Business, Intune, RMM tools, or WSUS-style controls, you may not see the preview update deploy the same way a home PC sees it. That is usually a good thing. Preview updates are best used on a pilot group first.
Business app compatibility gets a known-issue warning
Microsoft lists a known issue involving some third-party applications that launch Microsoft Office applications or documents. The affected Office apps may include Word, Excel, PowerPoint, Access, and other Office applications when launched from inside an affected third-party program.
Microsoft’s page names examples reported by users, including CCH Engagement, Workpaper Manager, dental software such as Dentrix and Softdent, and Zotero. The workaround is to open the Office application or document directly instead of launching it from the affected third-party application. Microsoft says a resolution is in progress and will be included in a future Windows update.
This is the part local businesses should read twice. If your office depends on accounting workpaper software, dental practice software, document-management tools, legal case software, tax software, estimating software, or another line-of-business app that launches Word or Excel for forms and reports, do not assume a Windows preview update is harmless just because it is not a security emergency.
Reliability and usability fixes are included
Microsoft’s KB5095093 page lists a broad set of quality improvements. The update includes reliability work across areas such as File Explorer, sign-in and lock screens, touch gestures, theme changes, desktop shortcut loading, Task Scheduler column-width persistence, font rendering for Greek and Cyrillic combining marks, and Microsoft Store download behavior.
The 26H1 KB5095091 page also lists several practical fixes, including improved Netlogon secure channel connections between member servers and domain controllers set up before 2025, BitLocker testing reliability improvements, a Recycle Bin confirmation-dialog fix, and a Windows Push Notification Services fix that could affect Outlook and other applications that use WNS.
Watch-Outs Before Installing
This is optional, not urgent for most users
Because this is a preview update, most home users do not need to chase it manually tonight unless they are trying to fix a specific problem listed by Microsoft or they are comfortable installing optional Windows previews. The next monthly security update is the more normal install path for most customers.
Line-of-business software should be tested
The Microsoft Office launch issue is the clearest business caution. If an update can interfere with how a third-party business app launches Word, Excel, PowerPoint, or Access, that can interrupt real office workflows: tax prep, dental charting, document templates, reports, export routines, billing forms, and client deliverables.
A small pilot test is better than discovering the problem on every workstation the next morning. Choose one or two non-critical machines that resemble the computers used by your accounting, front desk, operations, or management staff. Install the preview update there first, then test the actual business workflows, not just whether Windows boots.
Custom Windows images need Secure Boot deployment care
Microsoft includes a deployment warning for organizations applying dynamic updates to existing Windows installation media. Microsoft says the boot.stl file must be included as part of the installation media. If it is missing, devices might fail to start from that installation media and show error code 0xc0430001.
That does not affect most home users clicking Windows Update. It does matter for IT providers, managed-service providers, schools, larger offices, or anyone maintaining Windows install images, recovery media, or deployment workflows.
Backups and recovery keys are still basic hygiene
Even when an update is routine, the restart is when people find out they have no recent backup, no BitLocker recovery key, a failing drive, or a business app that has not been tested with newer Windows builds. Before installing optional previews on business machines, make sure important files are backed up and that BitLocker recovery keys are accessible for managed laptops.
Small Business Rollout Guidance
- Do not push this to every workstation immediately. Treat it as a preview unless Microsoft later changes the guidance or you are fixing a specific issue.
- Pick a pilot group. Include one everyday workstation, one laptop, and one device that uses important business software.
- Test real workflows. Open QuickBooks, dental/practice software, tax software, document templates, scanner workflows, exported Excel reports, Outlook, VPN, printer drivers, and anything that launches Office files from inside another program.
- Watch Office-launch behavior. If Word, Excel, PowerPoint, or Access fails only when opened from another application, use Microsoft’s workaround and open the document directly while you document the affected workflow.
- Check update controls. If your business uses Intune, Windows Update for Business, RMM patching, or local policy, confirm whether preview updates are allowed or held back.
- Review deployment media. If you maintain custom Windows images, confirm your process includes the correct
boot.stlfile when applying dynamic updates. - Plan the restart. Do not install optional preview updates during payroll, month-end accounting, patient scheduling, point-of-sale hours, or remote-work peak time.
Home-User Guidance
If your Windows 11 PC is working normally, you can usually wait for the next regular cumulative update. Optional previews are useful, but they are not mandatory for most people.
If you do install it manually, save your work first, plug in laptops, make sure your important files are backed up, and expect a restart. After the restart, check the basics: Wi-Fi, printer, Outlook/email, browser, OneDrive, VPN if you use one, and any specialty software you rely on.
If your computer is managed by work or school, do not install optional updates just because they appear. Follow your organization’s IT policy. Managed devices may hold preview changes until the next security update or until IT approves them.
Apple/macOS Check
Apple’s official security releases page did not show a new June 23, 2026 macOS security release, Rapid Security Response, or Background Security Improvement with a same-day macOS advisory at the time of this article. Apple’s page listed macOS Tahoe 26.5.1 from June 1, 2026 as the latest macOS version and showed the prior May 2026 macOS security releases below it.
Mac users should still keep Software Update enabled, especially for security updates and background updates. There simply was not a new same-day macOS security advisory to report in this Windows-focused update check.
When To Call The IT Guys
Call The IT Guys if Windows Update is failing repeatedly, a business app stops launching Office documents, BitLocker asks for a recovery key, a workstation will not boot after an update, or you need help deciding whether optional preview updates belong in your patch process.
For small businesses around Port Saint Lucie, Jensen Beach, Fort Pierce, Vero Beach, and nearby areas, the best patching plan is boring and repeatable: known backup status, a small pilot group, scheduled restart windows, line-of-business app testing, and clear documentation of what changed.
Related Reading
- 5 PM Tech News Recap for June 23, 2026: AI Patching, Post-Quantum Deadlines, GitHub Actions, UniFi KEV, WhatsApp Malware, Windows, And Prime Day
- Important Tech News Roundup: June 17, 2026 – FortiBleed, Joomla, Microsoft Defender, Office, Gemini, And AI Access
- Important Tech News Roundup for June 4, 2026: npm Malware, Cisco Patches, Windows Drivers, Android Security, and AI Controls
Official Sources Checked
- Microsoft Support: June 23, 2026 – KB5095093 for Windows 11 versions 25H2 and 24H2
- Microsoft Support: June 23, 2026 – KB5095091 for Windows 11 version 26H1
- Microsoft Support: Windows 11 version 24H2 update history
- Microsoft Windows message center
- Microsoft Security Response Center: June 2026 Security Updates
- Apple Support: Apple security releases
Bottom Line
KB5095093 is worth knowing about because it previews Windows 11 behavior that may matter to businesses, especially around Secure Boot certificate maintenance, optional update handling, Office-launch compatibility, and deployment media. It is not a same-day emergency security patch. Home users can usually wait; businesses should test deliberately.