10.68 to Mt Lion, need recommendations

[sbstrum]

I thought I was pretty savvy re the iMac and I am very happy with my i7 16GB RAM and with 10.68. But all these "upgrades" have created a problem for me:
1. Some vital software will not run on 10.68 and requires 10.7 or beyond. I did install 10.7, 10.8, 10.9 and recently 10.10 on my MacBook Air (MBA) but did not feel it ↑ my enjoyment or efficiency. But my working computer is an iMAC. I did install Yosemite on a newly partitioned internal 2TB drive that came with the iMAC. 400GB in partition 1 for data, 600GB for newly clean install of 10.10 and 1TB remains unused but thinking maybe for Time Machine backups.

I installed 10.10 just to see how it would perform on my iMAC as a bootable drive while preserving my 10.68 with all working apps. I did not install and bring over all my apps, etc from 10.68 to the 10.10 install.

Now I see a lot of issues unresolved with 10.10 and want your opinion on:
1. Can I erase or overwrite the 10.10 drive with Mt. Lion or Mavericks?
2. What can you suggest on whatever I install to equate with a clean install?
3. Any other thoughts or recommendations?

 

[sharon22]

This is just my personal opinion, but I would install Mavericks.

Mavericks is "well aged" in that most of the bugs have been worked out. Yosemite is still.... well.... in it's "infancy."

And, if it were me, I would do a CLEAN install, all the way!

I would use the Mavericks Installer to first completely ERASE the disk. Then, I would install Mavericks. That way, even the Recovery Partition will have Mavericks on it. Then, as far as your Apps, just migrate them over using Migration Assistant.

Most importantly (do NOT omit this step) be sure to back up anything that you'll be upset with if you lost. I'm a bit confused by your post -- I'm not sure if you have all your Apps on one drive or not, but if that's the drive you are going to overwrite, then be sure to back it up first, just in case things go wrong.

 

[chrfr]

1TB remains unused but thinking maybe for Time Machine backups.

Do not use a partition on a disk as a backup for the other partitions. When the disk fails, you will lose all of your data, backups included.

 

[Traverse]

As chrfr said, don't use the same disk for data and backups.

I think the jump to ML is nice for app compatibility. Personally, I'd recommend Mavericks. It's been the most solid version since SL for me. The UI is only a subtle refinement in most places, memory compression makes a huge difference even compared to ML and I'm starting to see a lot of software requiring 10.9. So, Mavericks will be more future proof, sadly I think older versions of OS X will be left behind sooner as focus on new Yosemite designs.