KB5083769 Windows – Misryoum reports that Windows 11 April KB5083769 update can make VSS-based backup tools fail on 24H2 and 25H2, with a VSS timeout error.
A Windows 11 security update is causing backup software failures, and the trigger appears to be timing out the system’s snapshot service.
Misryoum reports that the April 2026 KB5083769 update is breaking third-party backup applications on Windows 11 24H2 and 25H2. Multiple vendors are seeing reports from users whose backup jobs fail during snapshot creation, pointing to a VSS service timeout as the core problem.
In this context. the affected backups are generally those that rely on Microsoft’s Volume Shadow Copy Service (VSS). which coordinates snapshot activity between the operating system and backup or business applications.. When VSS doesn’t respond within the expected window, backup routines can stop before they complete.
This matters because VSS is a foundational component for reliable snapshot-based protection. When it becomes unstable, even well-configured backup setups can miss their restore points, turning routine maintenance into an urgent troubleshooting task.
Misryoum says the issue has been observed with software that includes VSS snapshot workflows across a range of products.. The problem has been tied to known behavior affecting tools from Acronis, Macrium, NinjaOne Backup, and UrBackup Server, among others.. For example. one commonly reported failure message indicates the backup didn’t finish because Microsoft VSS timed out during snapshot creation.
Acronis has also acknowledged the disruption, noting that the update may introduce system-wide issues affecting Microsoft VSS operations, which can lead to backup failures. In some cases, Misryoum reports that systems may also lose connectivity with a cloud management console and appear offline.
As a temporary workaround, affected users are being advised to uninstall KB5083769 via Windows Update’s update history, then pause Windows updates and reboot the PC. Misryoum adds that this approach is intended to restore backup functionality until a permanent fix is available.
The broader takeaway for Windows users and IT teams is clear: even security patches can ripple into operational tooling. especially where backups depend on specific OS services.. Misryoum recommends checking backup logs and validating snapshot success after any major update before relying on the next scheduled job.