In the Windows 10 Fall Update, scheduled to be released in September, Microsoft has taken steps to boost protection against ransomware attacks. According to their Insider Preview blog, the Fall Update will introduce "controlled folder access" to Windows Defender Antivirus
According to the post, "We’re making it easier for you to protect valuable data from malicious apps and threats, such as ransomware. To enable the feature, search for and open the Windows Defender Security Center from Start, go to the Virus & threat protection settings section, and set the switch to On. Controlled folder access monitors the changes that apps make to files in certain protected folders. If an app attempts to make a change to these files, and the app is blacklisted by the feature, you’ll get a notification about the attempt. You can complement the protected folders with additional locations, and add the apps that you want to allow access to those folders.”
You will be able to override access for apps that you know and trust but that are being blocked by the Controlled folder access feature. You will also be able to add additional folders to the list of protected folders, but you will not be able to cannot alter the default list, which includes folders such as Documents, Pictures, Movies, and Desktop.