Take Ownership on Windows 10
Update: Now there's a nice tool with an interface that you can use instead. Reset Files Permission
After installing Windows 10, you suddenly don't have permissions to save in some locations. It doesn't matter if you're an administrator either.
After some research, I found a simple solution in this thread on TenForums.
Simply fire up a command prompt (hit Windows key, type CMD, right click and choose Run as administrator) and run this command on your location or drive (change E: to appropriate):
icacls "E:" /setowner "Administrators" /T /C
Depending of the number of files in your location, it might take some time.