A problem has been identified with Windows 10 Update 1809. After this update has been installed, files have been reported as missing. This update has been pulled, so it is under investigation on a replacement.
If you have already done a manual check for updates and have this missing files issue, please minimize your use of the affected computer and contact Microsoft at +1-800-MICROSOFT. You can also use a different computer to access https://support.microsoft.com/en-us/contactus/ to also get assistance.
If you have manually downloaded the update and have not installed it, then do not and wait for the new update when it becomes available.