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Fusion drives by definition fused, not split. Fusion Drive is a hardware-locked solution,

https://eclecticlight.co/2015/12/27/fusion-drives-the-best-thing-to-happen-to-el -capitan/

http://arstechnica.com/apple/2012/11/fusion-drive-quick-look-our-predictions-con firmed/

http://apple.stackexchange.com/questions/168723/i-think-i-messed-up-the-fusion-d rive-on-my-1tb-imac-with-bootcamp

https://discussions.apple.com/thread/7453778

diskutil info -all

This is best one:

https://www.lifewire.com/setting-up-fusion-drive-mac-2260165

Yes, you can also do it manually. I don't agree that a cache cleaning is not so useful as stated. It doesn't change your machine, of course, but when a machine configuration is changed some cache files may not "match" the new config creating trouble. As an Apple technichan I perform such a task everytime the hardware or sw config changes (like minor or major OS updates). Especially i do perform it also BEFORE major OS updates and i NEVER had updates' problems (my High Sierra was a Yosemite in the beginning on the Mini). Check

majortom1967 wrote:

I don't believe the problem is in splitting the Fusion HD. Just try deleting completely and deeply all caches with Sierra Cache Cleaner. It often repairs strange problems.

You're free to suggest whatever app you like but as a rule "cleaning and anti-virus programs" are frowned upon for Macs on ASC. Sierra Cache Cleaner is both.

I don't mind about generic cleaning and never talked about antiviruruses. I'm maintaining mire than 110 Macs between friend and costumers and cache cleaning solved and (maybe) prevented lots and lots and lots of strange problems and never had a single problem. I'm not saying this is the solution for our mate but I believe it's harmless and worth a try (sorry for my English, ).

majortom1967 wrote:

I don't mind about generic cleaning and never talked about antiviruruses.

No but from Northern Softworks site…

Sierra Cache Cleaner helps protect your system from malware. SCC adds three additional layers of malware protection to Sierra, and ships with the powerful ClamAV antivirus built in. SCC can scan your downloads on the fly providing industrial strength virus protection from Mac and Windows threats.

http://www.northernsoftworks.com/sierracachecleaner.html

SCC doesn't install any kind of option it includes, therefore neither an antivirus. It does contain an antivirus but if you want to use it you must MANUALLY run it. Each time. Therefore I don't see any kind of hazard there...

Regadless this misunderstanding I'm interested in svedel's problem to be solved.

majortom1967 wrote:

It does contain an antivirus but if you want to use it you must MANUALLY run it.

I guess I misunderstood what "MANUALLY run it. Each time." means then. Enjoy the rest of your day.

svedel wrote:

Hi LeroyDouglas.

Thank you for your input. But I was hoping for an answer to #0.

Best regards

Søren

How to fix a split Fusion Drive - Apple Support

It was a really bad idea to split the drive. Don't know what to suggest until the Fusion drive is repaired.

svedel wrote:

Hi Dialabrain,

A Fusion drive consists of a standard SSD, and a standard 2.5" harddrive. There's no risk of any kind.

Except it doesn't work as designed. But, it's your iMac.

I have no interest in discussing Fusion technology thank you.
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