Taking iMac from Snow Leopard to High Sierra

[TitanTiger]

My wife was just given an hand-me-down 2009 iMac 27" (iMac 10,1) for her department and it's still on Snow Leopard. I want to get it to High Sierra, which is the latest version it can handle. I've purchased a Mountain Lion install from Apple and now I'm just trying to think of how to proceed.

Do I have to do anything special to do this like USB drives or other external drives to do the install from, or can I just upgrade in place? The plan is to update to Mountain Lion, then download High Sierra from the App Store and upgrade that.

 

[Juicy Box]

AFAIK, you can upgrade right to Sierra, but I strongly suggest upgrading to HS before doing a HDD-to-SSD swap.

I also strongly suggest doing a HDD-to-SSD swap, just do the upgrade of the OS first to the internal drive.

I attempted swapping the drive on a similar iMac running an older OS, had everything installed fine, but was unable to install High Sierra due to not having firmware that would only install on an OEM drive.

I put the HDD back in, and upgraded to HS using the HDD, then swapped the SSD again, and HS installed fine on the SSD.

 

[TitanTiger]

AFAIK, you can upgrade right to Sierra, but I strongly suggest upgrading to HS before doing a HDD-to-SSD swap.

I also strongly suggest doing a HDD-to-SSD swap, just do the upgrade of the OS first to the internal drive.

I attempted swapping the drive on a similar iMac running an older OS, had everything installed fine, but was unable to install High Sierra due to not having firmware that would only install on an OEM drive.

I put the HDD back in, and upgraded to HS using the HDD, then swapped the SSD again, and HS installed fine on the SSD.

Good to know. Right now, I think they want to keep the 1TB HDD over getting a faster drive. But if they want to move to that we should be on HS already and it would be rather seamless.

Apparently, you have to at least be on Mountain Lion to go to HS so I can't just jump straight to it from Snow Leopard. I just wanted to make sure I didn't need a bootable USB or anything to do this.

 

[Juicy Box]

I just wanted to make sure I didn't need a bootable USB or anything to do this.

Now that I think about it, I never upgraded any of my Macs to ML, but I purchased Macs that had it installed.

I would assume that you just upgrade to ML via the App Store, but you might have to do some searching for a ML link.

As for the SSD, I know that you were going to use the HDD for now, but the SSD would make a huge difference. A night and day difference between the two. You can get a 256GB SSD for really cheap at the moment, and if you have any experience messing around with computers, you shouldn't have any issues doing the install yourself using the ifixit guide.

RAM is pretty cheap too and could make a big difference as well depending on how much there is in there now.

 

[TitanTiger]

Now that I think about it, I never upgraded any of my Macs to ML, but I purchased Macs that had it installed.

I would assume that you just upgrade to ML via the App Store, but you might have to do some searching for a ML link.

As for the SSD, I know that you were going to use the HDD for now, but the SSD would make a huge difference. A night and day difference between the two. You can get a 256GB SSD for really cheap at the moment, and if you have any experience messing around with computers, you shouldn't have any issues doing the install yourself using the ifixit guide.

RAM is pretty cheap too and could make a big difference as well depending on how much there is in there now.

Yeah, we are maxing out the RAM to 16GB (it currently has 4GB).

As for ML, it was the last version that was a paid upgrade ($19.99) and you have to purchase it from Apple and then send you a download link for it. After that you can go through the App Store.

 

[TitanTiger]

Well the upgrade went off without a hitch. Also as it turns out, I didn't need to go to Mountain Lion first. You can go from Snow Leopard to El Capitan and from there to High Sierra or Mojave (if your Mac supports it).

 

[M3Stang]

Now that I think about it, I never upgraded any of my Macs to ML, but I purchased Macs that had it installed.

I would assume that you just upgrade to ML via the App Store, but you might have to do some searching for a ML link.

As for the SSD, I know that you were going to use the HDD for now, but the SSD would make a huge difference. A night and day difference between the two. You can get a 256GB SSD for really cheap at the moment, and if you have any experience messing around with computers, you shouldn't have any issues doing the install yourself using the ifixit guide.

RAM is pretty cheap too and could make a big difference as well depending on how much there is in there now.

This. Every older Mac I buy gets an SSD put in it after I verify it powers on. These days, SSDs are so cheap, you'll quickly recoup the money in lost time waiting for things to load. Something like $30 for a 240GB one?