(1) Your CBS.log is "too big to preview". Please delete everything in it except the date of the run, which I guess was 2/16/18. Then I'll try again.
(2) Please answer the other questions in my last post - you answered item (7) only. Give me an answer or a comment on items (1) through (6). For item (1), the question is: Did you go into BIOS Setup & move something above the Windows Boot
manager? But go answer them all.
(3) I'm not sure I like seeing the clone HDD plugged in at the same time as the original (or visa versa). That's a third candidate for the inability to upgrade. The upgrade may not like that.
(4) Do you have a Recovery USB Drive (ask Cortana for "Recovery" to make one) or Win 10 Installation media? This may be needed in case of catastrophe. Let us test it this way...
Edit: The BU folder will not auto-create. So, first:
MD C:\BU
(a) At a DOS Prompt: BCDEdit /Export "C:\BU\BCD Backup"
Also: BCDEdit /Export "C:\BU\BCD Copy"
Now you have a backup BCD that can be recovered. Also, you have a copy that we can play with.
(b) Boot to the Recovery USB drive or to the Installation media.
If to the Installation media, choose "Repair this computer" (instead of to install).
(c) At the "Choose an option" screen, click "Troubleshoot > Advanced Options > Command Prompt".
(d) At the Command Prompt: DIR C:\BU /a
Also: BCDEdit
Do you see the files listed? If not, I guess try letter D:, in case they have switched. Which letter gave you the files? Did you get output for BCDEdit, (just to prove it is there should it become necessary)?
(e) Close the Command Prompt, & click "Continue" to return.