I would not expect 102.10.1 to have caused such a problem, based on the minimal changes made in that release.

102.11.0 is out. Please update.

Thanks for your response. I have updated to 102.11.0, but the problem persists. On my old computer (Windows 10, Thunderbird 102.10.0) I can easily drag/drop addresses from an address book to a mailing list I have created under it. On my new computer (Windows 11, Thunderbird 102.11.0), when I drag/drop one or more addresses from an address book to a mailing list I have created under it, even though there is no red-circle "do not enter" image on my cursor, when I open the mailing list, it always says "no contacts available."

Thanks for the screen shots - I misunderstood your problem. But I'm still quite certain it's not because of any code change in 102.10.1 - https://bugzilla.mozilla.org/buglist.cgi?bug_id=1793918%2C1827503%2C1720257%2C1826374%2C1826127%2C1828366&list_id=16543598 lists the changes.

Open Tools > developer tools > error console Attempt your drag and drop check the most recent entries in error console

Attached is the list in the error console. Since I have only had this computer for a couple of weeks, I assume that all the errors come from the many times I have tried to do this drag/drop. Does this help in diagnosing the problem?

Thanks. Unfortunately nothing in there sheds light on your problem.

Are you able to create new contacts in your address book? And you are able to add contacts to lists without drag and drop? And these persist across a restart of Thunderbird?

Thanks for continuing to work on this problem. I think progress is being made.

I find that I can drag/drop emails from my other address books into my “Volunteers 2023” address book, and from there I can drag/drop them into my “Volunteers a” mailing list. I can also type a new contact into my Volunteers 2023 address book and from there drag/drop them into my Voluntters a mailing list.

However, none of the emails I import from my Excel .cvs file to a new address book can be moved to a mailing list I create under it or to any other address book or mailing list.

I assume this means the problems lies in importing an Excel .cvs file into Thunderbird. I have tried this several times with the same result. (By the way, most of my address books originally came from uploading from Excel.)