backup applications

The KB5083769 security update released in April 2026 has disrupted the functionality of various third-party backup applications on Windows 11 versions 24H2 and 25H2, primarily due to issues with the Volume Shadow Copy Service (VSS). Affected applications include Acronis Cyber Protect Cloud, Macrium Reflect, NinjaOne Backup, and UrBackup Server. Users have reported receiving an error message indicating that backups have failed due to VSS timeouts. Acronis has acknowledged the issue, stating it affects both Windows 11 Pro and Home editions, and warns of potential broader system issues. A temporary solution involves uninstalling the KB5083769 update or pausing Windows updates. Additionally, Microsoft has issued out-of-band updates for critical issues affecting Windows Server systems and warned that some Windows Server 2025 devices may encounter BitLocker recovery prompts after installing the KB5082063 update.