Well, PrPro will help you do this. When you have Moved everything to the external, and Open the Project, the program will ask you, "where is file ____?" When you navigate to that location, all linked Assets in that folder will then be found. You will need to repeat for each folder. When done, the PRPROJ will now reflect those new locations.
One can go into the XML file, the PRPROJ and alter the Path, but this can mean a lot of Search/Replace and can lead to problems, if not done correctly.
Third, with fast externals, like FW-800, or eSATA's, one can edit to/from. This is what I often do, as I migrate Projects between computers. In Windows (and would assume on the Mac), one can set the assigned drive letter in the OS. I do this for all computers, so my Z:\ is always my Z:\, regardless of where it's plugged in.
Hope that this helps,
Thanks again Bill. Good info.
Most welcome, and I hope that you are able to get your Project moved smoothly and efficiently.
If this is a one-time operation, and you will not need to do a migration again, I would just let PrPro ask for the location, and then point it to the new drive letter. As I mentioned, PrPro is pretty smart, and will go through each folder, that you have used, gathering up links to all Assets there. Depending on one's folder structure, this might have to be repeated, until all Assets have been linked. At that point, I am always going to do a Save_As, incrementing the Project file's name, so that the original is untouched - just in case one has to either go back, or something bad has happened. I do not like doing a lot of Saving OVER a Project, if I have done something like migrate a Project. I want a handful of Project files, just in case. Even when editing, I utilize the Save_As (or even Save_As_a_Copy), when major edits are done. For a bit of background on the differences between the Save operations, see this ARTICLE.