Just hope you don't get a windows update in the meantime, that reboots your pc
https://support.microsoft.com/en-us/help/4026834/windows-10-defer-feature-updatesThis link does not apply to Windows 10 HOME edition.
edit: as a side note, when i rebuild the posts of one of my forums which has over 500,000 posts, that batch normally completes in just about 2hrs.