HI ALL,
Marcum Reflect Home Edition V6.3.185 (UEFI
I can’t prepare Windows PE Image to create a Rescue Media on W10 Pro Laptop.
“Creation of rescue media will require a 774.0 MB download from Microsoft’
Downloading stops between 12-30% with message
“An Error has occurred and not all files have been received” Try again / Cancel
Have the same error after trying again multiple times. Please help.

I would try using the Download Agent to select the PE file package and download that separately.  If there is a problem on Microsoft's end, the transfer should theoretically fail in the Download Agent, too.  You can then point the Rescue Media Builder to the ZIP file the Download Agent acquired.  You can then, also, keep that ZIP stored somewhere should it be needed in the future.


To get the Download Agent, go to https://www.macrium.com/products/home and select the 30 Day Free Trial, which will send you the agent.  This link is for the Home version.  If you have another version, go to the necessary site for your version and choose its free 30 day trial link.

Fyi you posted this in the Reflect V8 forum even though you're apparently running V6.  But every time I've seen this behavior, it has turned out to be third-party anti-virus that is blocking downloads or extractions.  It might be because the WinPE package includes utilities that can do things like modify partition boot sectors, which can be used for malicious purposes but also have obvious legitimate use cases for recovery operations.  That might even affect downloading WinPE using the download agent as dbminter suggested.  If so, then if you're running third-party AV, try disabling it.  If that doesn't work, try uninstalling it, since sometimes AV doesn't allow itself to be totally disabled and yet still doesn't advertise when it's interfering with any system operations, which of course makes troubleshooting exciting.  Macrium has a KB article about anti-virus applications here.