Hi All, I thought of sharing some of my experience i had with Lion/Mountain Lion on my iMAC. First of all i would like to say that my iMac is not top of hardware anymore. here is what i have: CPU 2.66 Intel Core 2 Duo Memory 4G 1067 Mhz DDR3 iMac 24 inch Since i bought my Mac (4 years ago) i never did a clean install so i gradually upgraded over the years from Leopard to Snow Leopard, Lion, and Mountain Lion. After every upgrade system looked fine. However few weeks after i upgraded from Lion to Mountain Lion my system became extremely slow. Even just browsing the web became a nightmare. Not to mention using Photoshop which was really hard to work with. Looking only at the CPU and memory i could not identify what was going on because in general no process was taking over the resources. What i have noticed however is that the HDD was having a lot of activity. I disabled indexing since Lion days and i disabled it again after upgrading to mountain lion. However i did not see any improvement. The disk space utilization was not extremely high. I was still having 100GB free on my disk but i had only one single partition. I hoped that the 10.8.1 would fix my issue but i did not see any improvement. Because i suspected something might be wrong on the disk i decided to create two different partitions so after i freed more space (300GB) i started the disk utility and wanted to create another partition. Process started fine but it got stuck in the same place for more 2 hours at "resizing partition" or something like that. I did some reading on the web and i have seen users with similar experience that were stuck for even one day so i decided to quit the disk utility... what a mistake. After quitting this my free 300G became 20G free space or something like that. I did run a partition check and i have seen some errors so i decided to quit the whole thing. Now i am running snow leopard again (fresh install) and i feel like i have a brand new Mac (that is because it is extremely fast compared to what Lion and Mountain Lion was). I am not sure what is going at apple but feel very disappointed. At the moment apparently they advertise officially that the only method to get Mountain Lion is to upgrade via AppStore (no CD/DVD install), but apparently the upgrade process screwing up big time. I also have a MacbookPro 13 inch, i5, 8GB running Lion since it was brand new and does not have any issue. so i guess the upgrading process apple is advertising is to be blamed or it is just that in order to run Lion/Mountain Lion one needs better hardware than Apple is advertising at the system requirements. Any thoughts?