If you upgrade to Sibelius Ultimate (subscription), you get a new library. However, this costs more annually than buying a perpetual Sibelius 7 license second-hand.
If the installer fails, it’s often because one of the large zip files didn’t download completely. Use a download manager or try downloading one part at a time to ensure file integrity. Missing Kontakt Player
However, finding, downloading, and installing this specific library in 2025-2026 can be a labyrinth. Avid has moved on to Sibelius Ultimate and subscription models; physical installation DVDs are obsolete; and broken links litter the internet.
If you still own these physical discs, this is the fastest and safest method. Insert the Sound Library disc. The installer should automatically place the samples into: