KB5078752: adds a warning dialog to help users

March 10, 2026—KB5078752 (OS Build 17763.8511)

This security update includes fixes and quality improvements that are part of the following update:

• February 10, 2026—KB5075904 (OS Build 17763.8389)

The following is a summary of the issues that this update addresses when you install this update. The bold text within the brackets indicates the item or area of the change we are documenting.

• [Windows System Image Manager] This update adds a warning dialog to help users confirm that the selected catalog file comes from a trusted source.
• [File History] Improved: File History in Control Panel when backing up files. New files with names containing some Chinese and Private Use Area characters can now be backed up.
• [Secure Boot] With this update, Windows quality updates include additional high confidence device targeting data, increasing coverage of devices eligible to automatically receive new Secure Boot certificates. This targeting is based primarily on client device diagnostic data; due to limited data, servers are unlikely to qualify, though not explicitly excluded. Devices receive new certificates only after demonstrating sufficient successful update signals, maintaining a controlled and phased rollout.