Is there a way to stop NetBeans scanning projects?

Hey George I don't know if this is much of an answer but I right-click and choose 'close' on the projects that I don't need open. There's no point in having all your past projects listed there. Just have the one that you are developing open. You can always reopen the other projects from the menu. Once all the projects you aren't using are closed they won't be scanned each time you start Netbeans.

In addition to creating smaller Projects for the folders you really work on and then a Project Group to group them (Mateng), you can try excluding folders that you will never work on such as images folders and so on. To ignore those folders, go to:

File > Project Properties > Ignored Folders > Add Folder...

From NetBeans Help:

The Ignored Files property is the opposite of the Include Path. These are files inside the PHP project that you want the IDE to ignore for FTP upload, scanning, etc.