I modified the 'com.apple.screencapture.plist' file and now my screenshots don't save
Assuming that you are running the latest version of macOS, with iCloud Drive activated and the "Desktop &amp; Documents Folders" option selected, the ~/Desktop is no longer your regular desktop folder, as it's synchronized with iCloud. 

My suggestion: drag any file from your desktop to a terminal window, and it will show the full path for the file in the desktop folder. 

Hope it helps.