ONEDRIVE WEB VERSION

You're using OneDrive only on the web to save C: space, and the Music folder has vanished more than once after uploads. Not installing the sync app does not itself remove files, so first determine whether they were deleted, moved, or uploaded under another account. On OneDrive.com, search for track names, then check Recycle bin. If you use Personal Vault, unlock it before checking because its deleted items are otherwise hidden. Sign out and verify every Microsoft account. If you have Microsoft 365 and the loss occurred within 30 days, open Settings and use Restore your OneDrive to return to a point before the disappearance; later changes are moved to Recycle bin. Personal-account recycle-bin items are normally removed after 30 days. Keep the external backup unchanged; do not upload again until you identify the account and deletion date. If nothing appears, contact OneDrive support with folder names and last-seen dates.