Hi! a little late and new to the party, but I had this same issue trying to transfer multiple samples from Ableton’s Core Library to my Digitakt.
The fix for me was to navigate to the Core library folder on my HD (Mac) and transfer the files directly from there.
Macintosh HD/Applications/Ableton Live Suite > Right-click > Show Package Contents > Contents/App-Resources/Core Library/Samples
Open the folder(s) for the sounds you want to transfer and drag and drop into DT. Tip: it was helpful for me to put the folder in list mode and sort by kind, in this case I am transferring only .wav files and hitting the space bar then using the arrow keys can preview the sounds before copying them to DT.
So far this has been flawless…previously I was dragging them directly from Live, and more often than not they were failing and I’m not clear why.
I’m also new to digitakt, only two weeks in.