How can I disable "Scan for external changes" in netbeans?

By Unmarking the checkbox here

Go to menu: Tools/Options/Miscellaneous/Files => ❑ Enable auto-scanning of sources

In Netbeans(Windows), Go to "Tools > Options > Miscellaneous/Files ", You will find an option called "Enable auto-scanning of sources".

In case if you want to manually refresh (scan) your sources. Then right click the folder in Netbeans Projects window (or any explorere window like Favourites, Files, etc.,) you will find the option called 'Refresh Folder'.

Note : This option will be enabled only after you disabled the auto-scanning options.

On Mac go to menu: NetBeans/Preferences/Miscellaneous/Files and uncheck ❑ Enable auto-scanning of sources

Works for NetBeans version 8.0.2, MacOs 10.10.2 Yosemite