There is a label entry, check that it is empty. If you have NO labels at all, maybe create a dummy label, just o avoid bugs related to an empty drop-down list for that field...
Which build # was this download done with? You can find the latest 3.5.5 in my sig-links, I think the latest 3.5.5 stable I tested was build 46552 I believe ...
You should consider sticking to that 3.5.5 46606 above (or in my sig.) which avoids auto-updates untill v3.6 will be comparable to (possibly better than.. ) 3.5.5 .
Your problem, gjm, is that you did not do the manual update recommended here by Sergey to this same build:
This is were they've disabled auto-updates by default all together so to avoid any update to 3.6 till it'd be usable...
You might be luckier with the latest build (replace the exe):
https://forum.utorrent.com/topic/115517-steps-to-take-if-you-are-having-trouble-installing-µtorrent-classic/