Forum Discussion
KnownStormChaser
Dec 07, 2025Copper Contributor
Unable to install 25H2 update using multiple methods
I have been trying to update my secondary laptop to 25H2 for several days unsuccessfully. When I try to update with normal Windows updates, it gives me this error message: 0x800f0991. I also attempte...
KnownStormChaser
Dec 07, 2025Copper Contributor
No external devices are connected.
KapilArya
Dec 08, 2025MVP
Try upgrading via Windows 11 Installation Assistant:
Let us know if this helps!
Note: Included link in this reply refers to blog by a trusted Microsoft MVP.