I renamed a file directory containing several PDFs. Consequently, Adobe Digital Editions says these files are missing when I try to open them and look at notes I made. There seems to be an obvious solution, but I'm unfamiliar with XML and don't want to screw things up. The file locations and a lot of other information for Digital Editions is in an XML file called Manifest. If I can edit the XML file to show the correct directory, I expect I'd be able to see these files and recover my notes. I'm unsure what Word for Windows may do (e.g., add or delete characters) when I edit and save the new Manifest. That might corrupt the Manifest and be extremely counterproductive.
Is editing the file locations in Word for Windows safe, so long as Digital Editions isn't open when I do my editing?
I haven't tried Word, and would be worried about what it might do. I would suggest that you make a backup of the manifest file in case there is a problem.
You might also want to consider a decent text editor such as Notepad++.
I can confirm that Notepad++ can happily edit manifest.xml files, but as Jim_Lester says, make a backup (especially if you are not used to XML).
You may well find that if you Open the .epub files from their new location explicitly from ADE (ctrl-O) that you will both be able to read documents and see the notes.
I can't vouch for that; but if it works I'd recommend it over editing the manifest file.