system
A chat on subreddit /r/pcmasterrace
human
You should have moved the user libraries (desktop, documents, downloads, pictures, videos, music) to the D drive. (Properties&gt;location&gt;move)

Then she wouldn't have had to think about it.
gpt
Indeed I should have. I’m my defense when I was building this for her first, we went over the drives available and I explained to her that NVME will be fast to run the OS, her programs and boot up fast, but size on it is a bit of a premium still, however if she wants a fast boot we can go with a second set of drives for storage. They’ll be slower but will have a lot of space for less. 

She said she’s good. She has a lot of external drives so she’ll keep using them. I got the 1TB just in case. Then she decides she DID want the large secondary drive. So I set it up. And since she’s had a PC before and when I would troubleshoot it, space didn’t ever seem to be an issue, it had a 1TB HDD, so I figured she’s good on using that and the externals. I built her this PC about 3 years ago. And it wasn’t an issue until now. 

She also has gotten progressively more…absentminded over the years. Like really he’s. Borderline some severe ADHD although she’s 55. She’s all over the place. Not sure how else to describe it. So maybe that has something to do with her organization on the PC.