Windows10 - Windows + Shift + S stopped working

Try to simply clear the clipboard data, it worked for me.

Quick solution:

1. Go to the Settings -> System -> Clipboard,
2. In the Clear clipboard data select Clear​​​​​​.

Step by step

1. Go to Start and open Settings.

2. Select System.

3. Go to the Clipboard settings.

4. In the Clear clipboard data section select Clear. 

Note:

You should probably have the Clipboard history option enabled too.