Hi Sgt_Strider HFSLIP doesn't do unattended installs; it slipstreams hotfixes into a Windows installation source. Hotfixes are extracted, and the files inside them are copied into the source, replacing existing files. The *.cat files are copied over as well so Windows setup knows that the updated (or new) files are OK. During Windows setup, the necessary registry settings from the hotfix installation INFs are applied so Windows Update knows that they have been installed. Silent installers, MSI files and some hotfixes are not slipstreamed; they're integrated into the SVCPACK folder to be installed at T-13.