For a MacPro in a studio - no connection to internet, wireless units etc.
32-bit software only (Logic + plugins)
Priorities: reliability, low CPU/RAM load, troublefree.

Maverick or Snow Leopard - what say you experts?

Many thanks

I am no expert, but I have held off from upgrading to Mavericks and still use Snow Leopard here, though I use 64bit Logic 9, as I run large sample libraries.
I like the stability of my system, the fact that all my projects load and run perfectly well, and there is nothing that Mavericks and Logic 10 seems to offer that I really need as far as music production goes.
I also run Studio One, and the only thing that bothers me is being unable to use some of my favourite 32bit plugins in it. Abbey Road and liquid mix compressors, and CDSoundmaster's aqua stuff, whereas they run fine in Logic9 with the bridge.
There are just too many potential problems for me to upgrade yet, and I just cannot see where the benefits would be?
I was a little worried about being left behind by software developers (NI mainly) who are releasing plugins without Snow Leopard support, but in these cases I have been able to run the updates by fooling the system, and so remain up to date. There is also the added benefit of spending more time making music, and less time downloading, upgrading, reauthorising, tweaking the system etc.
When I see something which is really beneficial to music production, I will upgrade.

j bridge works well with S1 if you have vst versions...

As for OP, I'm on 10.8.5 and will not be upgrading anytime soon--learned my lesson, finally

Thanks for the reminder, I've been meaning to check it out.

Snowy, definitely. For a general rule of thumb, it's best to use a Mac OS that was made at the same time as the machine it's running on, or perhaps one generation after.

If you don't need to install anything new, you might as well stick on Snow Leopard. Some plugin vendors, such as NI, now only officially support Lion and up for the most recent updates, which may force your hand though.

Mountain Lion is a reasonable compromise that is compatible with most interfaces and software – but tricky to get hold of now if you haven't already bought a version through the App Store.

Surely it's not so difficult to buy Mountain Lion

OS X Mountain Lion - Apple Store (UK)

I didn't realise they still had on sale – I thought they'd removed it. Not such a problem then.

Any chance of some pointers on how to get the latest NI updates installed on SL? A pm is absolutely fine if you feel uncomfortable talking about it here. I would appreciate it immensely.

Mavericks is perfectly fine for many with DAWs, and most companies have caught up with updating (with a few exceptions). BUT my experience for the past two months is that 10.9 has done not much to improve my workflow and plenty to hamper it. Countless little things that I either hate the way something has changed or else are true bugs (external drives not spinning down, long wait stages in Finder actions, Mail still not working great, Safari runs poorly, memory leaks still with some major apps). I now have it on my non-DAW MBP to run some apps that require it, but whatever amazing 'under the hood' advancements that have been made are totally undermined by it running like a far from finished OS.

Going back to the 10.6.8 clone was like a shampoo commercial, running through a gorgeous field on a sunny day with a basket of flowers and my teeth suddenly glistening bright white.

Not a single feature of OS X 10.9 makes it a better choice for professional audio recording if you are happy with 32-bit software. The main features where social media and cloud based. 10.9 is way better than 10.7 or 10.8 but it is still not as reliable and snappy as OS 10.6.8 and probably never will be. Stick with 10.6.8 as long as you can.

Sure, it is pretty fast.
First Look for the prefs file: /System/Library/CoreServices/SystemVersion.plist and copy it to your desktop. Open it with text editor and change the ProductVersion from 10.6.8 to 10.7.
Copy the edited file back into the folder and replace the original, you may need to change the permissions on the System folder, or authenticate.

Now when you run the installers they will work.

Some people say they needed to update their version of NI's service centre, but I found my SL version was fine.

Make a copy of your present Service centre before you install anything just incase there is a problem with the Lion version not working after you revert the System pref file back to 10.6.8

I did this with Kontakt as the latest updates of some of my most used libraries would not install unless version 5.3 was installed, but Lion is the lowest OS that 5,3 will recognise. It also worked with the free compressor.
I haven't tried the latest Reactor updates yet.

I found a problem with the stand alone version of Kontakt not opening after the update, but copying and editing the minimun version pref file in the Kontakt app to 10.6.8 (right click on the Kontakt app in the finder to show package contents to find the file) and then dropping it back and replacing it worked.

I changed the system pref file back to the original after, just to be safe.

Wow, thanks for the tip. Make me wonder why NI wouldn't want me to install plug ins under SL? In my case the RC24 and RC48.

That's not been my experience. I experienced a considerable boost in performance upgrading from 10.6.8 to 10.9 with Reaper (32 bit) on a 2011 MacBook Pro. The only problem I've had is that the GUI doesn't work properly for some older (pre-2009) plugins. I can't speak to Logic's performance, though.

I guess because they don't want to spend time, effort, money etc. on continuing development and support for an 'old' OS.

Snow Leopard (10.6.8) if possible. SL is a lean, mean recording machine. Light footprint and fast. If your hardware doesn't support SL, then Mountain Lion (10.8.5).

Stay away from Lion (aka Apple "Vista"). Hold off on Mavericks until you really need those bloatware, iOS-type features.

Well....i was a committed 10.6.8/Logic 9 boy...until this past week.
Berlin strings and kontakt requirements made me go for the 10.8.5...and then Pro x just because i could..time machined to a new drive JUST IN CASE and went for it.
Like!
I had to adjust the actual angle of my monitors to suit the darker look better as looking down on them a bit more seems best......but it's ok i feel.
Getting used to it now...so far so good...not missing 9 in the least! (WELL..PERHAPS A BIT!)
that's a real surprise for me actually...i still got Logic 9.1.8 right there if i want it ...so...not a huge problem.
(If you got the SSL Native plugs...deactivate first or it's big problems trying to get them back! but that's been my only mistake)
Had to re-install Final cut pro also..that went very strange on me...apple support were excellent when i called them.
So all in all it went better than i had imagined it would...and seems very stable.

Maverick?
not so sure about that one.

it seems like you will have to take Snow Leopard out of my cold dead hands…. It has been really stable, and I really don't know why I would want to update (running a 8core 2009 tower), i don't need iCloud updates etc on my work system…. I have yet to hear of a reason to upgrade on my STABLE work machine excepting the above mentioned NI installer issues, which THANK YOU Zyzygis for your help on, (still haven't done, in the middle of a project finishing and am deathly afraid of bricking my NI stuff at the moment, but will this week), and I haven't wanted to use Logic X yet…. I just saw an ad for this product though:

32 Lives

32 Lives by Sound Radix, never heard of it before,…. new? any case, unless you bought a new system, IMHO i would linger on SL for awhile… but I could just be an old fashioned boob.

Upgrading an OS on my old Macbook pro lead to so many headaches I am now terrified of OS updates. My Mac Pro and my laptop are on Mountain Lion and that's were they'll stay for as long as they possibly can. I run Logic 9 and NI komplete 8 with a UAD Apollo at 64 bit. Everything works beautifully.

A word of caution for anyone planning to upgrade their OS - don't use the updater, only do a clean install.

I upgraded my Macbook Pro from Lion to Mountain Lion about a month ago and all I had were problems with the wifi and various other things. I spent countless hours on the phone with Applecare support but they could never fix the problem for me. Finally, I got fed up and installed the Mountain Lion installer to a USB flash drive and did a clean install to my drive. This cleared up ALL the problems i was having and now things are running smooth on 10.8.5. I've learned my lesson...

Definitely agree. Everyone upgrading should learn to make a bootable flash drive with your OSX version. Learn how to interrupt OSX boot and select a boot drive etc. Do a completely clean install from flash drive. Don't try a recovery update over wifi from the internet etc.

By clean install does that mean having to re-install all of your apps, this is quite a task.

I've downloaded the Mavericks updater to go from Mountain Lion but am a bit reluctant to run it.

surely if you are prepared and all backed up to do a clean install...it is worth doing the update install first to see where that leaves you?
the thought being that if it goes very badly you simply go ahead and do the clean install, and if it goes well you carry on and monitor the situation for a couple of weeks and then review.
p.s....i would stay with 10.8.5 for music right now anyhow.

Mavericks is actually brilliant for audio. Latencies are much reduced (which, for me, is a big selling point). Whether or not this is also the case with older machines I don't know... It's worth a try, I guess.

Besides the differing opinions what works (system details vs. software on each and every individual configuration)
10.9 is built so a lot of things which you ($$$) had under earlier versions won't run, which means more $$$ and hassle.
Worth it?
Get an empty harddrive, install 10.9 there, spend a whole day (or more, look up the many threads about downloading and installing LogicX), then try it. On a seperate drive! That takes the guesswork out of it. Then you will see if you can bring your work, plugins and whatnot over.

My personal opinion is OS "updates" come too frequent and don't offer that much difference. They seem to exist to force you into spending $$$ so you have mostly the same what you had before. More marketing than usefull code.

Yes, and it's quite a task. Because I have around 25 plug-ins it's daunting and it took me two weeks before I could say I had a similar functionality as with my SL install. BTW I'm speaking here about a clean ML install with Logic Pro X. Because of LPX bugs I went back to SL.

Personally I had bad experiences in the past with instaling one OS over another (Tiger > Leopard for example). While for other people it worked. You could of course create a back up of the current start up disk (for example with Carbon Copy Cloner) and then try out your luck with installing the new OS over the older.

Personally what I'm gonna do is puchase a new MacPro and gradually build up my system on Mavericks, while production work on old MP with SL continues.

I think professional audio recording had long been ready to take advantage of 64-bit's increased RAM accessibility, less data caching to the HD, and more tracks, instruments, etc. The real question is how many people doing professional audio recording will continue to be satisfied with 32-bit limitations.

That may very well be true for some but the OP specified his preference for a 32-bit setup. I have no problems getting 48+ tracks on my 32-bit system. Neither RAM nor data caching was ever an issue. It probably will become an issue if I switch my current system to a 64-bit system without updating my hardware first.

It wasn't the case not long ago, but these days it's so easy to clone your drive, install new system, want to downgrade but keep experimenting with new system, clone new install to spare partition somewhere and put clone back on your internal. There's really no reason to not check it out. Nowhere near the headaches of finding out that it breaks things ten years ago.

As a free update it's a no brainer to try it, especially given all the people for whom it has not been a problem with their DAWs, however random and unpredictable that may be.

Yeah, pretty much what NoVi and others have said. FWIW, it IS a pain in the ass but I didn't have a choice. However, a little preparation can make the transition a lot easier.

For me, two applications were lifesavers: Dropbox and 1Password. I have all of my registration info and passwords for all my software loaded in 1Password and I keep the master file synced on Dropbox. They make reinstalling stuff a lot easier.

First, I'd download all my current software installers and make sure they're compatible with the destination OS. I put mine on a 16GB flash drive. Then, I'd backup the important application files in Macintosh HD/Library/ and Macintosh HD/Library/Application Support/. I'd also go into Contacts to export all my contacts, Mail to export all my email, Calendars to export my calendars, etc. I'd copy these to the flash drive as well. And, finally I'd do a backup with Time Machine AND Carbon Copy Cloner! I used the CCC backup to retrieve big stuff like my iTunes and iPhoto libraries.

Next, it's time to make a bootable install drive. Here's an easy how-to for Mavericks: Clean Install Os X Mavericks Via Bootable Flash Drive

And finally, clean installing the OS and re-installing all the apps and documents. This part was the most time-consuming but in the end I have a fresh lean system without the remnants of past operating systems and orphaned applications/demos, etc. Good luck!