Comment 16 for bug 209513

I believe comment 12 is the key here. The dialogue has a very poor explanation but is trying to do the right thing. After confirming my configuration was similar to comment 12, I proceeded with "yes" and it all worked fine. I also noticed that my .config/user-dirs.locale contained "en-US" (my old setting) before accepting the changes and "en-GB" (the new setting) after accepting.

It is simply noticing either old default, manual changes, or defaults for languages that didn't used to have translations are pointing to the wrong place, and now we have a more sensible default - either triggered by user changing the locale or a translations update.

In my case it looked like it was trying to rename my Desktop to "Downloads". What is really happening is that my downloads location was in fact Desktop (I think this was the old default?), and it simply wanted to give it the proper name. I would guess that if you didn't trigger this by changing language, then your translations have been updated. For example, your English-India pack used to be missing the Music translation so defaulted to /home/user. When the missing translation is filled in, it tries to confirm that the setting is /home/user/Music, fails, and asks you what to do.

I think the behavior is desirable in most cases, but the explanation needs massive improvement. The only case I can imagine this being undesirable behavior would be if the user had manually (and deliberately) changed hiis directories from the defaults.