I have the new Mac Mini. I use Bridge CC's dialog to convert 3-5 raw images into a HDR.dng file. The previews look great but when the conversion is done, it looks like one of the raws, with blown highlights and dark shadows. Although the file size is now 100MB and can be re-opened in Camera Raw and re-balanced using the shadows/highlights sliders. But this redundancy should not occur. Is this a memory issue?
Be sure to have this setting checked while in the HDR window. This setting is sticky so that once it's set, it stays that way until you change it (or if you update your ACR or something like that, than it MAY change.) As such, if in doubt I do this before setting up a bunch of headless HDR processing.