If there's a title awarded for "most troubled Windows update," then Windows 10 version 1809 is a good candidate. Comically known as the October 2018 update, the latest version of Windows 10 is now widely available to users who manually click the "check for updates" button in Windows' Settings app.
Previously, version 1809 shipped with a particularly nasty bug that deleted users' documents and was stomped on a short while ago. Some folks with mapped network drives experienced trouble, an issue that was fixed on December 5. Apple provided an update to fix an incompatibility with iCloud, and Morphisec Protector and Cisco AMP for Endpoints also got fresh patches.
It's still not all roses for some users, though. Although Microsoft's website notes that anyone is free to manually install the latest revision of build 1809, the update is still otherwise blocked from automatic installation to some machines. Folks with Intel IGPs and graphics versions from 22.214.171.12444 or 126.96.36.19945, or with Radeon HD 2000-series and HD 4000-series graphics cards have to wait a little longer. Likewise, those using Trend Micro's OfficeScan or Worry-Free Business Security, or perhaps digging through F5 VPN split tunnels will need a little patience until further fixes appear from either Microsoft or third parties.