Hi,
Just thought I'd reply to this thread since I had the same issue (error 0x80070643).
For me, it was caused by my redirecting the default location for Program Files (and Program Files (x86)) away from my C: drive using registry, under:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion
ProgramFilesDir - REG_SZ
ProgramFilesDir (x86) - REG_SZ
ProgramW6432Dir - REG_SZ
I had to temporarily restore these values back to their defaults, then reboot and the Stablebit installer then worked fine.
Hope this helps anyone else with similar circumstances.
