Thanks for the response and suggestions. Yes, my cable and sd card are fine. I took your advice and temporarily disabled Windows Security (not sure what taming Windows Defender means or how to do that) before syncing and that did help with one of the issues. I was able to sync my entire library in one attempt. BUT since then I acquired some new flacs, imported them to the library, and I'm having the same issue I originally reported, which is that MC28 tries to re-upload files that are already on the device when I sync. Each of these files says Uploading... and then Error. This results in unmanageable sync times of 10-12 hours (if I were to let it play out). Instead I've been reformatting the SD Card each time I get something new in my music library and starting over with a fresh sync of the entire library. But that means sync times of 2-3 hours to add one or two albums. This can't be right. Shouldn't MC keep track of what's on the sd card and only try to upload new or changed files? How can I make that happen?