MacOS Snow Leopard on iMac 2010

OS X 10.6 was only ever released on DVDs. For an iMac 2010 model, you need the original gray OS X 10.6.x Restoration DVD which originally shipped with your Mac from the factory. That is the only way you will be able to install macOS 10.6 on that iMac. IIRC, the retail OS X 10.6.3 Upgrade DVDs (ones with the Snow Leopard pictured on the DVD) will not work since your iMac requires a later build than is available on the Upgrade DVDs.

Sandy849 wrote:

https://www.ebay.com/itm/276674393451?_skw=iMac+2010+restore+dvd+10.6.3&itmmeta=01JA74MRVWYSDWVNBQK9RZJEGN&hash=item406b14356b:g:xcUAAOSwcI5mMh3n&itmprp=enc%3AAQAJAAAA4HoV3kP08IDx%2BKZ9MfhVJKm%2B7CSw3cwYnUgFu9xsVWUO%2Be%2B891IC8Y0zVXLhuqdjgHJwcm%2FSwRa%2FHjNjCQ%2BWS3PKB1xhaPcmF70jY4vYf%2F0cGJRX4nUlQfdnsyk4T7K4R9Mc8f8fVOaCJutVWoPinI86%2FtTZQudR%2BO0TPkRuDL0GaBWYD1F5wrT%2BU4agwxXGB2N0ndsFvTmfGyj7IKlpLLIuShuEwkyUADrmiVUuDVNYX7nFh2dFhACfLlufCHN1S2OVcpcXvA2ua3qnLRm%2BLFxs%2Fo5%2BeMDZI%2BQpQXjVByeG%7Ctkp%3ABk9SR4SO0-TRZA I am not sure if these disks are compatible either

This one may be compatible since it is for a 2010 iMac. I have no idea whether Apple made one system specific Restoration DVD for the 21.5" and 27" iMac, or whether they each had their own specific Restoration DVD.

However, according to EveryMac.com, the build version for both 2010 iMacs is identical, so this one may work.

https://everymac.com/systems/apple/imac/specs/imac-core-i3-3.06-21-inch-aluminum-mid-2010-specs.html

https://everymac.com/systems/apple/imac/specs/imac-core-i5-2.8-27-inch-aluminum-mid-2010-specs.html

According to everymac.com, the mid-2010 iMac shipped with OSX 10.6.3 (10D2322a) and the April 2010 Snow Leopard 10.6.3 DVD was based on 10D575 — which as an older 10.6.3 release, and likely would not have the hardware support on the DVD for that July iMac as the gray discs that shipped with it.

Thus, in the absence of those gray discs, you would be done with older installations at OS X 10.7.5. The last operating system that this Mac supports is High Sierra 10.13.6.

Sandy849 wrote:

Ok I will buy the 10.6.3 disks

While you are at it, you might get Mac OS X Server v10.6.3 rev 1 Snow Leopard Unlimited Clients MC588Z/A.

Unlike the regular Retail version the Server version can be virtualized. I occasionally use old 32-bit Mac software via VMware Fusion VMs (free for personal use) in Sequoia (Mac mini 2018 Intel). Snow Leopard supports also old PowerPC software via Rosetta.

According to MacTracker there were four other builds for 10.6.4 for the 2010 iMacs....seems Apple was very busy. I don't recall any hardware changes so I think either one would be Ok. However, the seller for the 10.6.4 DVD you linked mentions a firmware difference that prevents the older 10.6.3 DVD from working. That doesn't quite make sense because Apple usually would update the system firmware using an OS update patch unless Apple never upgraded the system firmware for this model once it was sold. But it could explain why Apple kept releasing updated Restoration DVDs with new macOS builds. Unfortunately very few people would have such knowledge....after all who keeps track of firmware updates rolled into an OS update patch?

If that's the oldest version your computer supports, it is presumably the version it shipped to you running. Why not use the OEM installer disks that came with it and are supposed to be kept with it?