Doh! Waves and UAD both released updates at the same time. To make matters worse I just got the Native Instruments Komplete 11 Ultiamte installed too.
That’s Logic, Digital Performer, and Reaper all re-scanning the Waves and UAD libraries. Then Machine, Ableton and Cubase get their turn next. Then Finalie and Sibelius take their lovely time doing the same. Story of my life!