Hi i have successfully installed omni 3 with extenstions, trillian, keyscape, only bob moog dont work, so skip that one.

Spoiler: Instructions

Instructions:

DOWNLOAD Guiseppe version and the STEAM folder in that thread at another web page.
If you dont know which i would assume it's ok to reveal the site in a PM.

Also these instructions might work with the upload here on AudioZ

DELETE everything about omnisphere VST2-3, AU, APP
~/Library/Preferences <- omnisphere.settings and net.spectrasonics.v9.plist

Save your own library and patches you made, which is in user folder. Or save everything but you need to delete everything and do a fresh install, old patches will work later.

Steps:
Move STEAM folder with Omnisphere in it only. to ~/Library/Application Support/Spectrasonics/

open terminal: sudo chmod -R 777 one space after 777. Drag STEAM folder after it has been put in the right folder above. Then run the command.

Also make sure all omnisphere folders are read and writeable, this is what the command does.

Then you install Omnisphere 3 with in my case guiseppe version, SAVE instructions and go offline
Codesign one at a time the VST3, AU, APP with one space after each command, drag and drop
sudo xattr -cr
sudo xattr -r -d com.apple.quarantine
sudo codesign --force --sign -

Now you can run the keygen and open Omnisphere APP or in DAW ( be offline ) click the offline activation code and use the challange code that is after ch=

You open the R2R.exe with in my case lastest Crossover for Mac 25.0.1 Windows 10 64 bit bottle.
You can open with other stuff but i did this,

Challangecode example:

ch=SqbxHwLEPq34DV2chkAPrUqTx%3F%259 <- USE AFTER ch= so correct code is SqbxHwLEPq34DV2chkAPrUqTx%3F%259

Then activate omnisphere with right steam folder in place and you should already have done the sudo chmod -R 777 command.

now it should be activated and working, INSTANTLY go to ( remember to be offline and save these instructions )

~/Library/Preferences and find

net.spectrasonics.V9.plist and right click lock the file, deny read and write, or just write. But you can lock it also.

Open omnisphere make sure it finds the library it should, or you did smth wrong.
Give full disk access to Omnisphere.app and used DAW's in settings / integrity

To ensure patch saving when reloading projects.

Now it should be up and running, now you can re install or move sonic extenstions, trillian library, keyscape etc.

I moved the STEAM folder to external drive opend DAW and it asked for folder, and made the link automatically, but i had patch saving issues, so i use the original folder, with no problems atm.

I had a problem with patches from trillian not saving, so i downloaded the latest patch update for trillian which is rather old but works fine now.

I think this is pretty much everything. Comment if you have issues, but read carefully and do exactly as instructed.

Regards

Johnny