A: Possibly because it contains old or unsigned drivers. More likely, you downloaded from an untrusted source. Always verify the SHA-1 hash.
was the first major feature update for Windows 10, released on November 12, 2015. It is widely remembered for maturing the OS into a version Microsoft finally felt "confident" recommending for full business deployment. Key Features & Enhancements windows 10 version 1511 build 10586 iso
Where to Find & How to Use Windows 10 Version 1511 (Build 10586) ISO (November Update) A: Possibly because it contains old or unsigned drivers
The included Microsoft Edge (original EdgeHTML) is obsolete. You can install Firefox ESR or a legacy version of Chrome to maintain basic web functionality. was the first major feature update for Windows
Build 10586 was significantly more stable than the original RTM build (10240), with performance in everyday tasks—like boot times—reporting improvements of up to 30% faster than Windows 7 on some devices.