I sometimes want to go between different versions of the same project to pick up old or modified MIDI tracks, check Effects.
Most of the time I shut audio core off, then load two versions, and drag parts, VI's I need.
Other times I go to older version and export the track, (Midi audio), or make a channel strip.
Yeah waiting for audio core to initialize is frustrating
MacPro 2015 12 core - 64 gig of ram
Logic Pro 10.6
RME fireface 800, Genelec 8040A's
Genos, Montage,Motif XS Rack, Korg M3, Intrega 7, Falcon UVI, Kontakt, u-he, musiclab
Kontakt, UVI, U-he, Music Lab- Modartt
Kontakt and UVI libraries, U-he, Madrona Labs, Music Labs, Serum, Synthmaster, Seaboard Rise, SWAM
SampleTank,Falcon,UVI, A.I.R. MusicTechnologies