Absolutely not, just contact us and we'll issue you a new one.
The app supports only Windows, macOS and Linux.
There is no limit. YouTube shows the number of videos in the playlist, some have been deleted/removed/banned, some are duplicates, and so it's not an accurate number.
Please update to 18.104.22.168+ version, you can download a build for your operating system on that page
No, your code is valid for all minor updates.
YouTube has started blocking user's IP for heavy downloads. As a workaround, try entering your credentials in Preferences -> Authorization
If you get this error on almost all YouTube videos, please, update to 22.214.171.124+ version, you can download a build for your operating system on that page
Your playlist is private, so make it public before downloading or setup YouTube Authorization in the application Preferences
Try to enable safe download mode option in the Preferences->Network. It will reduce amount of connections to YouTube and prevent its ban.
Probably you have set your output folder to the folder located on external drive/usb stick with NTFS file system. macOS includes only read-only support for NTFS-formatted partitions. You can read more about NTFS on Wikipedia
This means that all streams in this video are DRM protected and cannot be downloaded. You can read more about RTMP protocol and protected streams on Wikipedia.
Open the app Preferences, it's located under the small gear icon at the bottom-left corner of application window. Next open the Audio or Audio tab, depending on what are you downloading, and choose desired iTunes/Music options.
Check connection to YouTube.com in the application Preferences. Open Preferences and switch to the Network tab. There is a small indicator which displays connection status to YouTube server. It is located at the bottom left corner. If it's red then something is blocking an internet coonection. Check your firewall and antivirus or specify correct proxy settings.
Check the Output folder setting specified in the Preferences. To do it open up the app Preferences and switch to the Audio or Video tab, depending on what are you downloading. Next, specify a different output folder with a write access.
Yes, you can backup the following folders AppData\Local\MediaHuman\YouTube Downloader\ on Windows and ~/Library/Application Support/MediaHuman/YouTube Downloader/ on Mac
By default all music files are saved to Downloaded by MediaHuman subfolder of your Music folder and videos go to Downloaded by MediaHuman folder in your Movies system folder. You can also open it by pressing ⌘ + J on Mac or Ctrl + J on Windows/Linux. To quickly open the location of a downloaded file, right-click on it and select Locate saved file
We don't recommend using the previous/old versions at all, however you can get some of them on this page
Please update to 126.96.36.199+ version, you can download a build for your operating system on that page