Windows 10 upgrade error

All,

I tried to update my Win 7 Pro desktop to Windows 10 this morning.

About two and a half hours into it I got a BAD_POOL_HEADER error and in
researching it it says it can be almost anything. Hard drive, memory,
registry, Windows system files, device drivers, and antivirus software.
That about covers everything.

It took me back to Windows 7. After reboot it told me this additional
information :

0xC1900101 - 0x4000D

"The installation failed in the SECOND_BOOT phase with an error during
MIGRATE_DATA operation"

After Googling it, the depth and breadth of the suggestions on how to
resolve it is staggering.

Memory test shows no errors, CHKDSK no errors, display driver is up to date.

I had every USB device unplugged except the mouse. Mouse driver is up to
date.

I've upgraded my home desktop and laptop, as well as another desktop here
at work prior to this. No issue like this.

Anybody seen this? Suggestions?

Thanks.