Now you've totally lost me Curt , (and I'm guessing this is due to my ignorance of Windows beyond 32-bit Vista  ).

But I haven't got the faintest clue as to what "the 256 folder (embedded thumbs)", "the 1024 folder (HQ thumbs)", "the Full folder is empty" (this last one sounds like Abbot and Costello to me) mean.

(FYI, the Mac equivalent of Windows Explorer is the Finder.)

As to your remark "I do not have "export cache to folders" enabled", I'm with the late, lamented Bruce Fraser when he wrote that, in his opinion, "that is sheer insanity." 

Curt Y wrote:

 

…Station_two I know you can find it, you just probably have never had the need to.

You got that right, Curt!     I'm just not in the habit of looking at my User Library (~Library) all that often.

So, I did find the following:

(I tried this in the Bridge CS4 installation, as I didn't want to switch to the MacBook laptop, which is my only machine that runs CS5 and CS6.)

~Library/ Caches/ Adobe/ BridgeCS4/ Cache/ 256/  ===>>  149 subfolders = 151.5 MB

~Library/ Caches/ Adobe/ BridgeCS4/ Cache/ 1024  ===>>  195 subfolders = 1.48 GB

~Library/ Caches/ Adobe/ BridgeCS4/ Cache/ data   ===>>     2 subfolders =  29.4 MB

~Library/ Caches/ Adobe/ BridgeCS4/ Cache/ full     ===>>  50 subfolders = 423.7 MB

So, I create a new subfolder in Bridge (Folders Panel), name it "CurtY-Test_folder" and stick 20 random images in it from a pre-existing folder through Bridge.

Now I see the following subfolders:

~Library/ Caches/ Adobe/ BridgeCS4/ Cache/ 256/ CurtY_TeD14513CB  =  584 KB

~Library/ Caches/ Adobe/ BridgeCS4/ Cache/ 1024/ CurtY_TeD14513CB = 3.3 MB

~Library/ Caches/ Adobe/ BridgeCS4/ Cache/ dat   (NO CHANGES HERE)

~Library/ Caches/ Adobe/ BridgeCS4/ Cache/ full/ CurtY_TeD14513CB =   12.1 MB

These are my relevant Bridge CS4 prefs:

Hope that's of some use to you, because I'm not sure what all this is supposed to mean. 

Curt Y wrote:

 

I thought I had Bridge cache figured out, but guess not.  Perhaps someone can enlighten me, or at least do a test and see if they get same results.

 

I used embedded thumbnails as it provides the fastest and smallest footprint (I thought).  I do not have "export cache to folders" enabled, and do not have "keep 100% previews" checked.  So therefore my expectation is that only the 256 folder (embedded thumbs) will be filled.  But the 1024 folder (HQ thumbs) is filled also, the Full folder is empty as expected.  The same sub-folder in 256 will be 2 megs while the 1024 will be 40 meg.  So the 1024 folder is 20 times the size of a 256 folder.

I think the 1024 folder caches preview files (thumbs are in the 256 folder).  So Bridge may generate preview files in the 1024 folder even if you have Prefer Embedded checked to not generate color-managed thumbs (in 256).