Ok, it's fixed now so it works with Youtube's current setup. Great plugin so I'm giving it 5 stars.

One thing that would be nice though, is if it correctly saved file names with the actual symbols in them. For example, it always turns parenthesis into dashes, so "(" and ")" always become "-". I think it also has done this with single-quote marks like the " ' " mark last time I tried it with a video that had a single-quote mark in its name. That really shouldn't happen with any of those symbols, as those are not invalid symbols in file names. So no need to replace them. In fact, the only symbols that AREN'T allowed in file names are the following:
"
%
/
\
|
:
?
*
<
>
And also, when correcting the name for a video who's title contains the double-quote marks like ", that should be corrected to the single-quote marks like ', not changed to a dash, for the filename.
So your plugin is still buggy as far as I'm concerned (and it will be, until all valid filename symbols are actually used by the plugin when saving files that contain those symbols in the video's title), so if I could, I'd give it only 4.5 out of 5 instead of a full 5 stars. But I can't select 4.5 stars, so I'm rounding up to 5 stars.

Overall great plugin, but still buggy because it turns many actually valid filename symbols into dashes, as if it thinks they aren't valid filename symbols.

Just realized something else. It doesn't copy all files to the selected download folder, only files that had to be combined. When files even don't need to be combined, they should still be copied to the selected download folder, as that's where I expect to find them. It used to do that. Your latest update seems to have broken that. So I've downgraded the rating of this plugin to only 4 stars. Fix that, either of these problems I've mentioned and your plugin will get 4.5 stars. Fix them both for a full 5 stars.