Spinning beachball upon wakeup from sleep
For about a week now I've been trying to resolve a problem with a spinning beachball upon wakeup of my iMac from sleep. Clicking the mouse or tapping a key on the keyboard will wake up the machine and present me with the login box. After entering my password and hitting enter the cursor turns to the spinning beach ball. The login screen remains displayed with the cursor spinning and nothing will happen until the machine reenters sleep mode. The only way that I can use the computer is if I turn off the power and restart the machine. I've scanned through the forum for similar problems and solutions and tried the following:
1) Apple Hardware Test - both normal and extended tests. No problems reported.
2) Reset SMC by shutting down the machine, unplugging the power cord, waiting a couple of minutes, reattaching the power cord and then restarting.
3) Reset PRAM by holding down command-option-p-r upon restart.
4) Run Disk Utilities to check for directory permission issues. There were some files/directories related to the HP printer that we use that were flagged as having permission issues. Fixed directory permission issues and reran the test where no additional permission issues were found.
5) Verified the boot disk (the 256 GB SSD) - no reports of problems were found.
5) I've inspected the messages in the console (many times over this past week) and there is no indication that anything untoward has occurred. I have a GRAID external disk that I use for Time Machine backups. Typically the backups happen late at night or very early morning. The last messages shown in the console are reports of the completion of backups. The messages log is then empty of messages for many hours - between the completion of backup and the first message logged upon reboot after I've had to power down the machine.
The machine is a mid-2011 27" iMac, 3.4 GHz i7, 16 Gb RAM, 256 GB SSD + 2 TB internal HD, 4 TB GRAID external disk used only for Time Machine backups. The machine came with OSX 10.6.8 (Snow Leopard?) installed when I purchased it, I've upgraded to both Lion and Mountain Lion since so am running OSX 10.8.4 now. I've been using the machine heavily for over two years without even a single hiccup. I've not installed any new software recently so haven't made any significant changes to programs or files. I'm soon going to be very reliant upon my machine for photo editing and uploading after a short break over the summer. Both of our kids are heavily involved in sports and I use my machine extensively for photo editing for club and high school soccer and high school lacrosse. I take and edit several thousand pictures a week (especially during late winter/early spring when both high school soccer and high school lacrosse seasons run concurrently). Our daughter's club soccer season begins this weekend with an out of town tournament. She'll have games for the next 12 to 14 weekends - 2 tournaments on consecutive weekends plus ten regular season games every weekend until mid-November. I have to get the problem with the spinning beach ball at wakeup resolved this week so that the machine is back into working order. I typically edit photos in the evenings after work and perform uploads to my photo hosting site overnight while I'm asleep. I'll leave my photo editing software open and running for days on end because it typically takes me two to three evenings to edit pictures from an individual game.
My fear is that since nothing else has worked that I'll have to reload the OS. Does anyone have any other suggestions that I might try before I take such drastic action?
iMac, OS X Mountain Lion (10.8.4)