Windows 10 uses peer-to-peer networking to reduce the strain on Microsoft’s Windows Update servers. Basically, this means that updates you’ve downloaded may be shared with other PCs on your local network and, potentially, with complete strangers’ computers via the internet.
How do you control it?
No personal data is ever exchanged with other PCs but, with this setting enabled (it’s switched on by default), you may find your internet speeds are slightly reduced, particularly when larger updates are being uploaded from your PC to others over the internet.
It’s even possible that it could nudge you over your monthly upload allowance, if you have one.
To change the setting, click Start > Settings > Update & security, then click Advanced options at the bottom. On the next screen, click Choose how updates are delivered. On the next screen, you have a choice. You can either switch this feature off altogether, or leave it on and switch it to PCs on my local network only.
The latter way, you’ll only be uploading updates to your own PCs, which won’t affect your internet connection and may potentially help you save bandwidth instead.