First, German Umlauts (ä,ü ...) but I think u have noticed this before.
Yes, I can confirm this is now fixed. Metadata is saved in two different PDF file places. In one of those, the XMP object, metadata was not being properly encoded by PDFE.
And worse then that sometimes the (Trial-?)Programm seems to ignore the changes that I made. In the Database everything shows up correctly but when I open the PDF in Adobe Reader the for example Autor remains the same (wrong one). It's about 1 out of 20 pdf's and I can't reconstruct why exactly these PDF's dont work.
For sure not a problem imposed by any intended trial version limitation. Trial versions are fully functional.
If the problem always happen with the same file(s), and you can't make it working for that particular file(s), even if trying more than one time, please send me one sample so I can check for what's wrong.
If it's random behavior, probably it's the, already know, file lock problem. In some system (I never experienced that), it seems Acrobat sometimes lock the opened PDF, even when PDFE instruct Acrobat to open a new one, and because of that PDFE can't edit the file metadata, updating only the database. The new, in development, build 59 version, (build 58 + patch4, for licensed users, already show) will show up a warning message, with a retry option as a workaround to the problem. Even so, I recommend that you test with another PDF reader. Foxit reader and the PDF-Xchange reader, both free, are very good and are not known to produce that problem.
You can also try to change the way PDFE uses the Acrobat reader plug-in, under the Edit>Preference>InternalPDFReader. Change from "Internet Explorer Default" to "Adobe Acrobat", and see if that change something. Take note that, to use the other two proposed readers, you must use the "Internet Explorer Default" option, and set the new reader as the default Windows Shell PDF files assigned reader.