New OS unstable?

Ever since I installed the Maverick OS on my Mac Pro, model 5.1, my computer will not sleep correctly. Most of the time, it refuses to enter sleep mode. When it does sleep, and I wake it, some of my external hard drives have become dismounted, and some programs are not in the state they were before the computer entered the sleep mode! Anyone else having similar problems?

Welcome to Mac-Forums..

I'm running Mavericks on my late 2009 27' iMac and have not see any issues with going to sleep. That's my normal mode of operation. I wake it up when I want and let it sleep after..

You might want to reset your PRAM/NVRAM to see if it does anything for you.

I assume that your previous OS (Mountain Lion perhaps) didn't have this problem?

Actually I had the opposite problem. In ML and Lion my macbook wouldn't wake from sleep without a lot of fiddling with the keyboard and/or mouse. now it wakes up as soon as I open the lid.
Have you tried running Onyx? Or at least repair permissions in Disk Utility.

New OS

I run Onyx on a regular basis, with a more or less standard set of maint. scrips. And I did reset the NVRAM as one of the actions I took. No luck. But both suggestions are good ideas! I also reloaded the entire OS!

I had no problem with the prior operating system. I noticed the problem within 24 hours of installing the new OS. It's very likely the problem was concurrent with installing the OS, since I would not immediately notice a failure to sleep properly.

I suspect it is a buggy interaction between some program element and the operating system. That will make it difficult to find, since I have a lot of programs on my machine. If I'm lucky, perhaps an OS update, or some program update will bail me out.

I'm not going to hold my breath.

You can do some simple trouble shooting by stopping all startup programs and removing all external devices such as hard drives. You might also try starting up in safe mode and see if the same problem occurs.