Hi Ardispicy,
Your post has been split to a new question.
The error is the same from the previous post.
Failed to get WimMount file version, C:\program files\macrium\reflect\wimmount.sys, 0x80070003
It appears there was a defect in a recent version of Macrium Reflect which fails to restore the path of wimmount.sys image path after uninstalling Macrium.
Fortunately the user in the forum post provided screen shots containing the values of the registry keys if you want to inspect your own system.
Key: Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WIMMount\ImagePath
Old Value: ??\C:\Program Files\Macrium\Reflect\wimmount.sys
Correct Value: system32\drivers\wimmount.sys
Note the user on the forum reports wimmount.sys was missing from his system32\drivers directory, however it *is* there on my system.
Changing this registry key on my system appears to be allowing the 1809 upgrade to progress beyond this particular failure now. Fingers crossed...