How to stop photoshop from taking up 140GB just from creating a new project

It is often the case when this happens, that units have got mixed up, and a document intended to be 1000 pixels wide is actually 1000 inches.  If that is at 72DPI then the document becomes 72,000 pixels wide, and that can easily produce a 140Gb of scratch files.  What's even worse is that a file that size can cause Photoshop to slow to the point of being unusable and crash, and if Photoshop does not shut down properly, those huge scratch files will be left on your hard drive.