Matlab doesn't have same rights as user

I'm sitting on a fresh installation of 2015b on windows 10. For some reason, I can't write to the Documents folder from inside matlab? My user has ownership of the folder, and both administrators, the user and SYSTEM has "full control". Running matlab as administrator does not change anything. I can edit files in Documents from other programs (or, at least wordpad) with no problems. The result is the same whether I try editing existing files, or saving new ones. Apparently, matlab is still able to write to the desktop folder, but I can't see what the difference between the two locations is.

any ideas?

[Walter Roberson]

Duplicates http://www.mathworks.com/matlabcentral/answers/318226-matlab-doesn-t-have-same-rights-as-user