I just messed up my catalogue, BIG TIME. I created some folders in Windows Explorer and sorted my existing source folders with original photos into these folders. Of course, this raised question marks inside Lightroom (meaning: the link to original source images was lost).
I didn't know how to solve this problem so I did the right click on the top folder in hierarchy and chose "Synchronize folders". This properly removed and re-imported all the photos, now sorted into my newly created subfolders by years BUT all the edits are now gone. No picks/rejects, star ratings, color labels, preset edits, nothing...
Is there a way to bring this back? Are there original .xml's stil present, can I somehow make Lightroom re-connect those or not?
Do you have a backup of your catalog file before you made this error? If so, all of your problems can be solved by using this backup of your catalog file.
XMP files (not .xml files) may or may not have your edits in them, but the catalog is where your edits are definitely stored, and so if you have the backup of your catalog file, then you can solve the problem easily. Use the backup of your catalog file and follow the instructions here to fix the question mark icons: http://www.computer-darkroom.com/lr2_find_folder/find-folder.htm
IMPORTANT ADVICE: do not re-import photos; NEVER RE-IMPORT PHOTOS; and in this case, synchronize folders is also a terrible idea because it re-imports photos.