How do I import Bridge keywords and metadata to CS6 from CS4 so that I don't lose them if CS4 is not

Question

I have hundreds of keywords and metadata including Ratings and Labels using CS4 and Bridge CS4.
It is time to replace my PPC Mac with a new Intel Mac.
I am going to install CS6 on the new Intel Mac without installing CS4.
By default.... this eliminates ALL keywords and ratings and labels from my Bridge browser. The keywords will still be present on the files but Not present in Bridge keywords list and all ratings and labels will be lost.
Making a copy of Bridge CS4 metadata to another computer is quite simple.
Simply copy All of the Bridge CS4 application support folder to the other computer.
The question then becomes.... can I aslo do this with CS6 without introducing an incompatibility?
1. incompatible due to CS6 application support.
2. incompatible due to transfer from a PPC (APM) to Intel (GUID).
This concern results from an Bridge CS4 export problem I experienced.
Bridge CS4 will export all of your keywords and you can import them from a text file but it has some odd troubles. (try it and you will see)
This does Not mean that CS6 has the same troubles.
What do I require to preserve existing metedata and keywords that exist on a PPC using CS4 and import them into CS6 using Intel?
Sound simple?
I doubt it.
The points are.
1. CS4 not installed.
2. CS4 source is PPC not Intel.
3. Ratings and Labels are metadata that Are Not part of the file metadata and unique to Bridge only.
4. Keyword Search and keyword Use requires that Bridge have keyword list, otherwise Finder is the far more useful browser and the new version of Bridge will require hours of keyword listing.
I don't want to spends hours retyping keywords lists in Bridge.

Answer 1

Ratings are NOT placed into the file under CS4 Bridge and neither are
Labels.
That depends on your file type and settings voor Camera Raw.
Like Curt stated usually metadata is written in to the file itself. Only Raw files can't be written to and by default they create a XMP file, also called Sidecar XMP files (and do have the same filename, only a different extension called .xmp). These files are also by default hidden in Bridge but If you use Bridge to move files they travel along with the original.
If you move or copy them using finder you have to be sure these XMP files are also copied with the originals to the new location.
Using the menu View / show hidden files should reveal the XMP files.
An other option for the Camera Raw prefs is to set metadata to the Camera Raw database instead of written to sidecar XMP files ( to my knowledge using sidecar files has been the default since about CS3).
Now here it becomes a bit tricky and I only can tell you my findings, not to be confused with true facts. (and mind you, it is at least 5 years ago I was on a PPC and not even remember which OSX 10 was able to work on it, I just present the acting of CS6 on an intel Mac Pro with OSX 10.7, but I don't believe the difference in location is that much)
Having written the Metadata to the Camera Raw Database your image settings get written to a file in the user library preferences folder called logically "Adobe Camera Raw Database". But also some info gets added to the Camera Raw Cache folder (User library / Caches/ Adobe Camera Raw) in a file called index.dat.
Also not having set metadata to xmp sidecars stores the ACR settings in a new .dat file with a unique number (not to be traced as a corresponding filename. And also the default maximum is set to 1 GB of space and when full the oldest files are overwritten with the new ones.
Personally I use converted DNG files that are capable of writing metadata to so all info and settings are in the file itself and I don't need to bother about central storage that can get lost. The downside is that changes to a DNG need to save the whole file instead of a small xmp file and probably reading cache takes more time then getting info from central storage but I like to be on the safe side and speed is not really needed to be nailed down to split seconds in my workflow.
Keywords are stored as a file in the Bridge preferences but Like Curt already stated exporting the old list first and then via the same route import again to CS6 should solve your problem and they will be back as persistent, otherwise the files in the content window show as italic and sadly enough have to be made persistent one by one with right click mouse menu, so that is not really an option for you.
Exporting the list does create a text file that can also be altered manually with a simple text app and as said, again be imported in newer versions as Curt described earlier.
Making a copy of Bridge CS4 metadata to another computer is quite simple.
Simply copy All of the Bridge CS4 application support folder to the other computer.
Well, in fact it is true to call copying this folders a simple task but replacing the existing new CS6 would not be my method. The biggest change for Bridge CS6 was the transition to 64 bit and I lack the knowledge for this but also cache format for thumbs and previews has been different for every version.
But if you have located the CS4 folder for Bridge in your PPC user library / application support / Adobe / Bridge CS4 you should find a file called 'Adobe Bridge Keywords.xml' and it is fairly safe to replace this CS4 version with the new CS6 version.
Also custom settings for the output module can be copied (however to my memory the option for custom settings in Output where introduced in CS5) and collections can be copied.
So for your keywords the copy option might work, rating and labeling for Raw files they will be read in CS6 if they are stored as XMP. ACR settings idem but CS6 ACR has a new (2012) conversion mode that has different settings that do not work with previous settings (unless you first choose to use the 2010 conversion as default Raw setting.
If it is in the Central Data Base I would start trying to replace the CS4 with the CS6 edition (after back up of existing CS6 version) and see what happens. If it works your out of trouble.
You can also open the Camera raw Database as a text file but there is a lot of data in. Maybe scripting would be able to reveal those data and transfer to XMP but you have to visit the dedicated Scripting forum for this.
And while you state to have not installed CS4 anymore it might be wise to reinstall it (but first make a proper back up of the previous mentioned folders and files to be on the save side.
This gives you the opportunity to export keywords properly and if needed you can use Show Items from subfolders option with filter and set preferences to XMP sidecar to refresh the rating and labels to those XMP files. Just an escape route that might not be as painstakingly as it looks at first sight, just use the options for Bridge to filter.