Do you use the upgrade option from within system settings, or the option to download the Mac OS installer from within the OCLP application? If you havent tried, try using the OCLP application and choose "create Mac OS installer" (or something very similar, don't remember the exact wording on the button, and download the Mac OS version you intend to update to. When OCLP asks you after the download if you want to create a installer choose no. The installer file is now in your application folder and you can manually click it to start the upgrade. Remember to root patch after the installation, and if you can I recommend to hook your mac up by ethernet during the upgrade in case the wifi drivers arent supported prior to root patching.Following a successful upgrade on my MacMini to 15.0, I was attempting to do the same on my iMac 27" 13,2 But it seems to be acting pretty strangely. It takes awhile to get to have the Upgrade Now screen appear and following my clicking on it, nothing happens. Waiting longer, it goes back to the same Upgrade Now button screen.
I've attempted to reset SMC And PRAM.
Still no joy.
Any ideas what else I could do?