The recent KB5083769 security update, released in April 2026, has inadvertently disrupted the functionality of various third-party backup applications on systems operating with Windows 11 versions 24H2 and 25H2. This issue, first highlighted by Microsoft MVP Susan Bradley, has raised concerns among users relying on these applications for their data protection needs.
Impact on Backup Software
At the heart of the problem lies the Volume Shadow Copy Service (VSS), a crucial component introduced with Windows Server 2003. VSS facilitates seamless collaboration between the operating system, backup solutions, and essential business applications like SQL Server and Exchange. However, the recent update has led to VSS service timeouts, resulting in backup failures for numerous software products.
Among the affected applications are notable names such as:
- Acronis Cyber Protect Cloud
- Macrium Reflect
- NinjaOne Backup
- UrBackup Server
Acronis has acknowledged the issue in a support document, noting that it impacts both Windows 11 Pro and Home editions. Users have reported encountering the error message: “The backup has failed because Microsoft VSS has timed out during the snapshot creation” following the installation of the KB5083769 update. Acronis further cautions that this update may lead to broader system issues, potentially disconnecting machines from the cloud console and rendering them offline.
For those affected, a temporary solution has been proposed. Users can uninstall the problematic KB5083769 update by navigating to Settings > Windows Update > Update history > Related settings > Uninstall updates. Additionally, pausing Windows updates and rebooting the system may help mitigate the issue until a more permanent fix is provided.
In a related note, Microsoft has recently issued out-of-band updates to address other critical issues affecting Windows Server systems, which had been experiencing restart loops and update installation failures post the April 2026 security updates. Furthermore, Microsoft has alerted users that certain Windows Server 2025 devices may encounter BitLocker recovery prompts requiring a BitLocker key after the installation of the KB5082063 update.
