I do this with some regularity to save space on my SSD. When I do, I typically create a data structure on my alternative disk that matches the data structure of my profile folder, so that (assuming a user name of "JohnSmith" which is not likely to be the one that you use)......
C:\Users\JohnSmith\Documents (\Music, \Picture, \Videos, etc. etc.)
Has the same data structure on the other drive, something like
D:\Users\JohnSmith\Documents (\Music, \Picture, \Videos, etc. etc.) or in your case K:\
Once that data structure has been created, I then use file explorer to browse to the original location C:\Users\JohnSmith\Documents (for instance) right click that folder, choose properties and use the "Location" tab and the "Move" button to relocate the contents of that particular folder to the corresponding folder within the data structure that I have created on the alternate drive.
This technique has always worked for me.
NOTE: Do not attempt to move the entire Profile folder only the contents of the individual folders within the individual profile folder.
I also strongly suggest that before moving forward you make sure that all your critical data is backed up to an external resource and safe and you might want to consider also creating a disk image just to be extra safe
https://www.windows10forums.com/threads/please-for-your-own-peace-of-mind.794/