What are these green checkmarks on my Desktop icons?
Solution 1:
Apparently the checkmarks may have been added by Microsoft OneDrive. (Source)
Another cause can be Norton backup flagging the files as backed up.
Pressing F5 or right clicking the desktop and choosing 'Refresh' should get rid of the checkmarks. (Source)
Solution 2:
I have found a different solution for this problem.
I had this problem too, but I don't have Norton nor One Drive. So i looked further. On the Microsoft forum I found a simple trick that worked for me.
If you right click on an empty space on the desktop and then 'refresh' the green check marks will disappear
It only seemed to affect the desktop shortcuts, nothing else. For more details you can read the article on the microsoft forum what is include in this post.
Link to Microsoft forum