Q: imac won't switch off or reboot after AV file deletion

Avira.

I am not sure what I deleted, they had non-word names as if written in code. Impossible to remember and I didn't write the names down. However, installing Yosemite does not seem to have replaced them as I had hoped it would and whilst I can stop worrying about the Permissions (thanks for that) I still have a system with constant freezes and spinning beach balls for operations that used to be instantaneous.

I tried to Repair Permissions in order to get the machine to work properly again; not only did it make no difference, every time I tried to do this the reboot loop began and the machine stopped loading half way through.

In Safe Mode the same error was still there, to the best of my knowledge. I didn't run it for hours like that - just long enough to see the same kind of problems still existed.

I'll take a look in the areas you mention. It seems to happen after some use, often on warm days, and as if the RAM gets filled up but never emptied, or the machine is switching between real RAM and virtual RAM (on the Hard Drive). The SSD part of the 3Tb fusion drive has a capacity of 1.25 Gb, of which 1.21 Gb is full. In old one disk systems when they got that full they behaved pretty much in the same way - slowly, hesitantly, and with odd problems that could not be fixed other than via making more space. I have a feeling one of the files I deleted said something about being a Device Handler or a file for controlling he memory allocation or something like that. Really can't be sure.

I'm pretty sure my machine is being spied on, and I know by who as well, because they know too much about who I email and when and where I am going without me telling them... which is why I installed the AV in the first place. :-/ I wanted to see if there was a key logger or other spyware on board.

The main problem now though is the memory swapping (if that is the problem) or the inability to cycle off or on properly without needing a 5 sec hard reboot...

Where do I find Internet Recovery and what if the internet is flaky too? Mine seems to have to reconnect every so often...

Thanks Barney, you really know your stuff! :-)

I am trying to avoid taking the iMac into an Apple Store due to its weight and the distance from car parking facilities, but I may have to. It doesn't help that the latest iMacs come in a not really reusable box for transport protection. Yes, the new sloped box probably costs far less money to make, but I believe it will also be the first Apple box that people won't pay for secondhand. It also didn't have that marvellous feeling of "Wow!" when I took the computer out of the box either.  And of course, this is a typical example of why shipping computers with an OS on a DVD will always be my preferred method.

Behaviour update so far: Login and Logout is quicker than with Mavericks, but I still haven't managed to restart it without the boot loop tripping it up. On the weekend I wanted to take a screenshot of part of an ongoing Skype call but while the first shot was instant, the second one took ten seconds from hitting Cmd+Shift+4 to actually saving the image, which by that time had already moved on and was no longer what I wanted.

I keep on thinking things point to problems with the Fusion Drive as the SSD is now effectively full, and there seems to be a lot of disk swapping going on. Add in some flakey internet/WiFi and these other inadequate responses and the machine is very frustrating to use. I've had Macs for 10 years now and this is definitely the worst hardware/software combination I've had. Tiger was a far more reliable and controllable OS; while the white iMac was my best hardware - although a Mac mini server used as a desktop at work is also very good.

Sorry to write so much.

I tried marking your reply as Helpful Allan Eckart, but Safari wouldn't let me. So I tried logging out of the Apple Discussions website and the window just went white with nothing happening. I clicked on the Back arrow and came back to here. The logout page uses a .jspa script I believe. Right clicking on links also means it takes about 10 seconds to get the context menu to show. Memory handling, screen rewriting and various associated functions are really f***ed on this machine!