I use the “Learn Spelling” feature quite a bit as some of my compositions require a lot of abnormally spelled words; words that are common but are alternately spelled for my purpose(s). The program (126.96.36.199) will not retain my spellings after exiting Scrivener and restarting.
Have you taken a look in your personal word list? That is under options / corrections and is in the upper right part of the window that comes up. There is the facility to add words there as well as the normal right mouse click on word. Not sure why your program is not saving them. The actual list is stored on your C drive, normally under Users / yourlogonname /Appdata /Local/Scrivener/Scrivener and there it is… wordlists.
Hopefully one of the users, Devinganger, will spot your post. He is a windows expert and could probably assist, as it may be windows related rather than Scrivener.
If Scrivener is not saving your new learnings, that in my experience indicates there is a permission issue – where Scrivener is trying to save the personal word list doesn’t permit it to save the file, or the file exists but has the wrong permissions.
I would first try uninstalling Scrivener, rebooting, and re-installing Scrivener as an admin user. This won’t remove any of your data but should help fix any permissions weirdness.
If that doesn’t help, email technical support and get direct help that way.