I'm a long time Mac user (my first 'Mac' was a Starmax 3200!) and I use my computers day-in-day-out for work applications. I'm a photographer and after 4 years+ with my iMac 5K (the original one) I got tired of waiting for the Mac Pro redesign and decided to plump for a 10c iMac Pro that became available via the refurb store. It arrived yesterday and is going back today. Sure, it's a point sample, but the experience I've had over the last 24hrs was the worst I've ever had with an Apple computer. The machine came with High Sierra on it (presumably the brand new models ship with 10.14) so I began by updating to Mojave. The installation never completed and the computer got stuck in a boot loop. After giving it 20 or so boots (to confirm that it wasn't going to eventually complete) I got bored of waiting around and turned it off. Eventually, I was able to get back to High Sierra, after a few trips to Recovery Mode. I found that elements of Mojave had installed. The latest version of Safari had installed but it wouldn't actually run under High Sierra and told me that Mojave was needed. Perplexed, having never seen anything quite like this, I ran disk utility and found some "crypto_val: invalid state.key_revision" errors that seemed linked to the 'Bridge OS'. For all my many years of Mac use, this was a little beyond me so I decided to erase the computer and begin afresh. Eventually I was able to install a new version of High Sierra, but when trying to update to Mojave I ran into further issues again. Eventually, I was able to upgrade to Mojave using a USB key that I prepared as a Mojave installation USB using Disk Creator from Mac Daddy. To get it to run, I had to invoke it from the High Sierra desktop. I tried doing it during boot, after using Startup Security Utility to allow booting from external discs but while it appeared to work initially it threw me back into High Sierra without running the update. So, I was now in Mojave. Further errors later, I finally managed to get the latest version of Mojave installed. Thinking all was well, and with a clean bill of health from disk utility I started getting a whole host of uncommanded restarts. The computer would just turn off in the middle of things and reboot. I tried all the usual stuff, resetting the SMC, removing peripherals, nothing seemed to help. Eventually I thought maybe it was a power issue so I tried plugging the machine into another socket in the house. Nothing helped. This morning the iMac Pro has restarted at least 10 times without being asked to do so. Each time, after booting it told me that an error had caused the restart. In short I am highly perplexed. This is the priciest machine I've bought from Apple by some margin and my experience was by far and away the worst. I've arranged a return and if they can find me a like for like model in the refurb inventory I'm going to try a replacement. I'd read some horror stories about the iMac Pro but assumed that they were the usual stories you read on web forums - every model has a few bad eggs right!? Perhaps that's the case here, but the machine was simply unusable. I know my way around Mac maintenance and this machine was simply not interested in playing ball. It leaves me decidedly skeptical, if I wasn't already(!) about Apple's position in my future. I rely on my machines for work and the iMac Pro lost me at least a day of useable time. Apple need to pull their finger out and commit to professional users or bugger off and make some more emoji. /rant In other news, I'd love to hear from anyone else that had similar experiences.