Why doesn't REAPER see the plugin after I installed it?
REAPER only reads the VST3 folder when it starts up or when you trigger a rescan. Quit REAPER completely, reopen it, then rescan plugins. If it still does not appear, the installer put the file somewhere REAPER is not looking — check the folder path below.
Plugin folder: Windows: C:\Program Files\Common Files\VST3 — macOS: /Library/Audio/Plug-Ins/VST3
Almost every "missing plugin" report comes down to a scan that never ran. Installing while the DAW is open is the usual culprit — the host has already built its plugin list for that session and will not go back for more.
The second possibility is a security prompt that was dismissed. On macOS in particular, a first-run block can leave the file on disk but unusable, which looks identical to a failed install from inside the host.
14 days free, no card required. Install the VST3, paste a lyric sheet, and record one take start to finish before you decide.
LyricsRunnerVST ships as a 64-bit VST3, which is the format REAPER uses for third-party plugins on current versions.
That is normally a blocklist entry from an interrupted first scan. Clear the plugin blocklist or cache in REAPER and rescan.