Microsoft’s Windows Defender Offline (WDO) product should be in the toolkit for every I.T. technician. If you are trying to run this on a very old Windows XP computer with less than 768KB of memory, WDO will display error 0x80508007 when starting up.
The error message displayed does not tell you what’s wrong, but the cause is not enough memory. WDO requires a minimum of 768KB of memory.
Microsoft’s article KB 2520970 includes a list of error codes you may encounter.