Stop Notepad++ warning if file has been modified from outside
Solution 1:
Settings -> Preferences -> MISC. tab
In the section that says File Status Auto Detection make sure that Enable is unchecked
Solution 2:
Settings → Preferences → Misc. → Uncheck Enable under File Status Auto-Detection
Also, as Jet pointed out, you can also have 'Update silently' checked if you want it to auto-update the file.
