This might be a Windows issue, but when I accidentally selected 150 x 32mb frames in a folder after double clicking the workspace to open an image, I could not stop the process. As soon as I realized my mistake, after 2 images opened (it takes ~2 seconds to opens each image) I tried to "pause/abort" from the Process Console. I could not stop the opening of images. After about 50 of them opened, and a coupe dozen clicks on the "pause/abort" button, the pop-up dialogue opened asking if I really wanted to abort, and the opening of images paused. "Yes" and "no" were not responsive. I could move the pop-up around on the screen and I could close it with the "X", but it would not stop the process. Closing the dialogue box would resume the opening of images. I ultimately had to terminate PI through task manager.