There are documents about how to remove such things. CNET's Cheapskate noted a method I use to dust it off.
https://www.cnet.com/how-to/how-to-delete-the-windows-old-folder-from-windows-10/
I find many users try to delete it. (Not how it's done.)
After 2+ years of running Windows 8.1 Pro 64-bit on my desktop - Intel Core i7 4770K, 16GB DDR3 RAM, 240 GB Samsung 840 Pro SSD as C drive, WD Black 1TB hard drives - I decided it was time to upgrade to Windows 10 Pro 64-Bit. Installation was done from the Full version on USB. While the installation had a few annoyances, all went well. Oddly, about 3 days after the upgrade attempts to delete the Windows.old file failed with "Access denied" notice. However, I noticed today, 5/13/17, that the file was no longer on my C (SSD) drive. Has anyone on this forum experienced similar behavior? Overall, I'm satisfied with the upgrade to Windows 10 Pro. It is my 3rd such upgrade. Thanks for your support.

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