is iMac (Retina 5K, 27-inch, Late 2014) compatible with macos high Sierra

knrm wrote:

... but this Imac have a 1 tb fusiondrive, and some write, that this drive simply does not work with High Sierra. Is it really so?

It is not really so.

I have a similar model computer, and High Sierra installed. "macOS High Sierra introduces APFS (Apple File System) to Mac computers. APFS replaces Mac OS Extended (HFS+) as the default file system for solid-state drives (SSDs) and other all-flash storage devices."

APFS will not be installed on your Fusion Drive.

knrm wrote:

Is iMac (Retina 5K, 27-inch, Late 2014) 3,5 GHz intel core i5, 32 GB 1600 Mhz DDR3, compatible with macos high Sierra.

Can't I find an official answer?

Yes, How to download macOS High Sierra - Apple Support lists compatible hardware.

You should also consider using RoaringApps to help you determine software compatibility.

Upgrading macOS without fear by John Galt is also a good source of information.

knrm wrote:

Thank you so much. I have searched your suggestions but found no answer.

I am not a technician, but this Imac have a 1 tb fusiondrive, and some write, that this drive simply does not work with High Sierra. Is it really so?

FWIW, I have High Sierra installed on two iMacs with Fusion drives and it works just fine.

Your mac can install High Sierra, the APFS file system is not supported in Fusion drives, but your disk will stay on the HFS+ file system, so there you go, go for it.

It just so happens that I'm using that exact same model iMac at the moment. High Sierra runs like blazes. Go for it.