Fixing MacMini (Late 2009)

I was cleaning up my closet and found that my MacMini was there all packed.  I kind of remembered that there was some problem with it, something like I couldn't start it up.  But I forgot exactly what the problem was.  Since I was about to throw it away, I thought it would be fine to turn it on the final time, and maybe yanked out the hard disk and destroy it desperately since I was a bit worry that people would steal my data from it.

I was surprised that I could start up the machine, and I was able to use it to surf the web.  So I was like, maybe I could try install the latest MacOSX Yosemite on it.  And that how my nightmare started.

I experienced the following problem:

• I was never able to complete the download of Yosemite through App Store. Usually in middle, or worst of all, at the near end of the download process, it would RESTART the download again, or gave me "failed to download Yosemite".  After experienced that 7 to 8 times (and wasted TONS OF BANDWIDTH), I knew that something is seriously wrong.  The trick of changing DNS didn't work.  After try and try and try for almost 3 to 4 hours, I ended up decided to try downloading Yosemite on my OSX Yosemite VM, and that actually worked.  I was planned to following this procedure and create an install dmg file, but then I thought, maybe I could try simply copying the Yosemite install .app folder from VM to my home file server, and then copied it to my MacMini.  Ended up I found that approach working well, so I didn't have to use the .dmg I created using this procedure.  Notice that I should NOT copy the .app folder to Application folder.  Instead I should just put it in some folder on local harddisk.  I tried putting the .app folder in Application folder, and it ended up that the App Store download progress override that folder, which wasted all the time I spent on copy over the file.
  
• I found my track pad clicking not responsive.  I had this problem for quite a long while, but never serious deal with it.  Today I finally fixed it by doing it old school: I used force to twist the track pad.  That fixed the problem (although the left corner is still not as responsive as the right corner).  If later on the problem comes again, maybe I'll try to do some proper fix.
  
• Even with the Yosemite installation file, I still had problem installing Yosemite.  A few times I tried, and the installation would ended up failing in the middle, and sometimes even crashed the machine.  Eventually I tried out swapping the 8Gb in the MacMini with the original 2Gb that came with the MacMini originally.  That of course means I had to crack open the MacMini.  But then I did that before, and I had the tool to do the job.  It turned out that the switching out of memory really did the magic, and I was able to complete the installation.  But then, running Yosemite with only 2Gb of memory was just slow (plus there's some serious problem with the internal harddisk, which I will explain later).  So I was trying to figure out whether BOTH of the 4Gb memory chip has problem, or just one of them.  I tried having 1Gb at the bottom slot, and one 4Gb at the top, and tried out another  installation of Yosemite.  I didn't go well. So I tried another 4Gb chip stay at the top slot.  This time the installation CRASHED in the middle of installation.  So it seemed worst then before.  Before I gave up on both 4Gb chip, I gave it one more trial by using the 4Gb memory chip I tried the first time but insert it in the BOTTOM slot.  This time the system seemed stable and able to finish installation.  So I am going to settle with this setting.  If eventually this setting fail,  then it means it's time to throw away this MacMini.
  
• After I had 2 Yosemite installed, one on internal harddisk and one on external harddisk, I started using Yosemite with the one installed on internal harddisk, but found that the performance being pretty sluggish whenever I tried to open a folder.  And then I tried the OS installed on external harddisk and the performance was so much better.  That's when I realized that there's something wrong with the internal harddisk, and in fact also explained all the problem I had with Windows 8 dual boot (Boot Camp) on MacMini as I was forced to put Windows 8 on internal harddisk.  So I am going to totally ignore the internal harddisk and just use the external one.

With the Mac Mini got fixed up, I don't have a need to buy a new MacMini anymore.  Sure I spent almost a day on it, but I kind of got some sense of accomplishment, just like what I got after I fixed up my Lenovo X60T.  BTW, I wonder if I can use the memory chip in X60T on MacMini, but that would be another day of adventure.