OK, so it's just slow loading the file.
Try changing the scratch disk -- yes, the external will be slower.
But I'm not sure why you're getting the spinning color circle - that means that the application is blocked and not processing events (which Photoshop should be doing even with a slow disk).
Are files that slow to load if you open a PSD from Photoshop? Or is this just with certain file types from Lightroom? (could this be ACR related)
I changed the scratch disk, to my internal which has 300G of free space but also kept my FW800 external 600G of free space as well.
Now things seem to be running faster.
I've tried opening .psd and .dng files, maybe the .dng files load a bit faster.
After I reinstalled i did a complete update againk which included ACR 7.1
I also tried reinstalling CS6 over itself, but not sure if that might have made a difference or not. The reason I did that is that I'm getting a separate error messge when I select PS Support Center.
The error messge states, Adobe Air, this application is damaged, try to re-install the application.
Keep in mind that external disks sometimes spin down, and thus the startup time could have been greatly extended by using such a disk in that condition, as it would have to be given time to spin up. It could be that it's an acceptable disk for the task otherwise.
Just thought I'd mention that.