Starting with System Center Configuration Manager, version 1702, unknown computers that are started from media or PXE may not find task sequences targeted to them. The SMSTS.log shows:
There are no task sequences available to this computer. Please ensure you have at least one task sequence advertised to this computer" Unspecified error (Error: 80004005; Source: Windows)
This issue may occur if the Previous button on the "Select a task sequence to run" page is selected on the unknown computer.
This is a known issue that is now fixed by applying Update rollup for System Center Configuration Manager current branch, version 1702.