CS5 Production Suite is the version.
Does the error occur in OS X 10.9? If not, why not remain at OS X 10.9? Is it necessary to run OS X 10.10?
The general rule of thumb is that when you are running software that is no longer tested or supported on a new operating system, you have to prepare for anomalies like this. You may want to install a separate bootable hard drive with OS X 10.9 on it so you can continue running that software more reliably.
Hope that helps,