Can't make new project: directory you specified is read only

I am running Cubase Pro 9 v9.0.1, on a Windows 10 version 1607 64 bit PC.

Overnight I have encountered the following problem which I have never seen before and which, as far as I am aware, I have done nothing to cause.

Whenever I try to create a new project in a new folder, Cubase gives me the error message “The directory you specified is read only! Please make a new selection!”.

My Cubase projects are contained in the folder c:\Users<my name>\Music. Using Windows Explorer, I can see in the Properties of the Music folder that there is a black rectangle in the Read-only attribute. I have tried removing that and applying the change to “this folder, subfolders and files”, but the change does not seem to endure (the black rectangle is back next time I check), and when I relaunch Cubase the problem remains.

Any help please on the cause of this, and how to cure it?

I seem to have fixed this. Predictably, it was a MS issue. I used the fix here:

I found there were two instances of me at step 4, one as an Administrator, one as an ordinary user. It was the latter that needed Full Control assigning. The update took a few minutes to apply.