iMac 2009 - working extremly slow


macrumors newbie
Original poster
Jan 14, 2019
Hi all,
I have a iMac 21.5 inch , Late 2009 with 16 Gb memory and 500 Gb SSD disk working on High Siera.
Most of the time I am using Lightroom and ON1 software for photo processing. Actually I would like too, because iMac working soo slow, and most of the time I'm sitting in front of the screen and waiting for response.
One year ago I was upgrade my Mac from 1TB clasic disc to 500 Gb SSD, and computer work faster for a while. But few months ago situation goes worst and worst. Now i am thinking about total reformat and clean install OS and all software, specially because upgrade was not clean install but only clone old disk to new one.

Is there anybody who have the same problems?
Did anyone have some better idea?

Thank you in advance,
All the best,



macrumors newbie
Jan 10, 2019
United Kindom
I had similar problems. The only thing I could find to fix it was switch off family sharing/backups/dropbox etc. I think the computer was spending a lot of its energy in doing these tasks in the background. It seemed to help.


macrumors regular
Oct 18, 2005
if you reinstall the OS, don't install the current one. The newer the system the more demanding the system is to the computers resources. I would not go higher than 10.8 myself on that processor.