So, I’ve finally updated Omnisphere 2 to 3. Took a backup of the Omnisphere subfolder inside the STEAM folder just in case (figured the third-party libraries, Trillian etc. won’t be affected by the update), then drag ‘n dropped the STEAM folder hosting the new Omnisphere 3 library on top of the old one as it is commonly suggested.

Some files were replaced, I think some new ones were added and things look ok for the time being, opened a few projects with Omnisphere 2 instances (including third-party libraries) and everything seems to load correctly.

However, since the new soundsources are located in:

C:\ProgramData\Spectrasonics\STEAM\Omnisphere\Soundsources\Factory\Core Soundsources (51.7 GB)

and the ones from Omnisphere 2 in:

C:\ProgramData\Spectrasonics\STEAM\Omnisphere\Soundsources\Factory\Core Library (53.9 GB)

the old ones (Core Library) stayed around. I guess I am supposed to simply delete this? I found the fact there is hardly any mention about it quite weird (only found 1-2 cases talking about it but without mentioning how they handled it) and since I wouldn’t want to screw up my Omnisphere installation by deleting Core Library if I shouldn’t or try other random stuff such as merging “Core Soundsources” and “Core Library” folder (this doesn’t seem right…) I thought I’d just ask around just in case.