By Arvy - 26 August 2016 7:04 AM
Have you checked the C:\boot\Macrium folder and its access permission settings. That's the target location where Reflect's rescue media "wizard" normally creates (or tries to) its WinPE rescue build that can be used as a system boot option and/or copied onto rescue media. If you can remove that folder manually, the "wizard" will (re-)create everything that is required on whatever drive is selected in Reflect's default settings (Other Tasks -> Edit Defaults -> Advanced -> Macrium Reflect PE Files).
If you wish, you can also delete the folders under "C:\ProgramData\Macrium\Reflect\Windows Kits" that are used as the PE-10 base source for creating and updating Relect's rescue media, but if you do that, the "wizard" will need to re-download the Windows Kit from Microsoft during the build process.