Martha,
As I said above, it's a Windows problem. The difference is this: Win-7 saves in the last known folder or the one that is named "Pictures" or any other folder you files into last. It'll go to that file when you want to open the file too. In Win-10, it saves in whatever file you choose. Then when you open the file you need to remember the folder where you filed it. That's because when Win-10 was made most people had several folders named "pictures".
The rest of us manage our folders by making saves in the "Picture" folder, then making more folders inside the "pictures" folder according to our methods or file system. We have files saved according to date -- or -- in my own method I have files saved according to the person I save it under as the name of my customers. So I save to "Pictures" then a folder called "customers" then to a folder with my customers name and inside that folder I sort what photos I had when I worked one time for that customer and then the next time I worked that same customer's Other photos. It helps me keep it perspective. I save in those "other" folders with the customer name and the dates to help me distinguish when I did that work. Now I can tell at a glance when I did that work instead of telling my customer, "I don't remember you" and "when did I do that?" I can get t heir name, look at my files, and even if it was 5 years ago, I now who, what, when and where. I have all my customers files re-saved in my external drives, and I have 3 of external drives. Whether if that's because I'm a software engineer who needs devices or if that's because saving in more than two places is needed today.
Everybody has their own method of saving. Its because the old folder of "pictures" was OLD and many didn't get along with only having ONE folder to lead everything.
Another has mentioned that you can save in an external drive and it will go there right away. Yes it will, but that's because its on a drive letter, not a folder name. So if you want everything on a drive then you need to either partition your drive, or use external drives. Trust an old software engineer, splitting drives on your C-drive is not a good thing because things become lost and weird after a couple of years with that. My method of working folders works better.
BTW, be glad you don't have Win-8. It was out to lunch most of the time, lost in its own world.
I'm a Windows guy. I come back here whenever there's a need to solve a Windows problem. It's not an Adobe problem. Adobe turns to Windows for its filing system. I think its a good system.
Win-10 uses NTFS not FAT. FAT (File Allocation Table) saved files to page frames and any page frame that was available, and it saved fast - but when we wanted to find those files, it took a long time to get through its index to find the files. With NTFS (New Technology Filing System) the files save where they should be, where a user wants them to be, then when we open those files, they come to the screen immediately. The only problem with NTFS is that it saves its apps and files in the same page frames (folders) as it did always, and that's when it slows down to find those page frames. NTFS needs to be accurate so it slow down. The page frames are larger with a 64 bit but still its the same old page frames being used. With 32 bit the pages frames were a tad bit smaller. This is the reason Win-10 doesn't have the same speed compared to Win-7 which has FAT.
Steve Lehman, MCSE
Kathie