Due to Mac updates we cannot officially support Mac OS 10.13
When downloading the libraries the download will most likely be successful until the unpacking process. The issue that Mac OS 10.13 users have had is that at the end of the Unpacking process they receive the message “Error. Please Restart Download" because the current version of the downloader is not compatible with Mac OS 10.13 and cannot unpack the downloaded files. It is unlikely that we will officially support it.
Please use the Unarchiver or Keka to unpack the downloaded zip files. You do not need to keep the zip files or unpacked folder. You only need to keep the folder that is unzipped. (Do not delete zip files before they have finished unpacking). You will need to make sure the library location is listed in the Directory list and then do a Full Rescan after the libraries have finished unpacking. Please note that sometimes this does not work. However, this is the only current solution other than updating your OS.