APFS in High Sierra causing problems for Unity Engine, Cities: Skylines, Civilization V, m...
Game development engine producers Unity has strongly recommended to its users to avoid the upgrade to macOS 10.13 for the moment, as despite the firm fixing a number of issues that plagued developers using the tool with High Sierra's beta releases, there are still some faults that need to be rectified to make the game engine stable on Apple's latest operating system -- and APFS is inducing problems in other game titles as well.

The iPhone Team Lead for Unity Technologies Mantas Puida advises on the company forum that its High Sierra upgrade recommendation is "better postpone it." A previous version of the post advises that there were "some issues" with the beta 1 release of macOS 10.13, which also advised holding off on upgrading until issues were fixed.
One major issue raised during the beta releases was of disappearing assets in Project View, which was found to be an interoperability problem between Unity and APFS, Apple's new file system. While patches for releases 5.5.4, 5.6.3, 2017.1.1 and 2017.2.0 RC 1 and later do fix the disappearing asset bug, Unity confirms there will not be any fixes to version 5.4.x for High Sierra, and that affected users will either have to upgrade their project to Unity 5.5.x and later or keep using macOS 10.12.
During the High Sierra betas, a number of forum posters found they could still use Unity by installing the tool and project files onto a secondary drive formatted as Mac OS Extended (HFS Plus), though it did not work for everyone.
While Unity has largely solved that problem, the firm advises there are still some High Sierra-related bugs that need squashing. Users are unable to use Local Cache Server in Unity, as this will crash the whole operating system, with the current solution being to disable it for the moment, though the remote version is said to "work fine."
Monodevelop, a customized version of an open source development environment that ships with Unity, was reported by users to crash at startup when in High Sierra, an issue that has also been fixed in Unity patches. Another Monodevelop issue, where the software crashes when it is dragged between monitors, has yet to be solved.
Puida does offer some general advise relating to testing beta operating systems, suggesting "Please consider installing it to a separate partition to not interrupt your everyday workflow." The same advice could be extended to newer versions of operating systems and software as a whole, especially when used in mission critical or production systems.
Issues with game engines and operating system updates are usually felt not only by developers but also by players. Reports from players of "Cities: Skylines" on Reddit, Steam, and in the AppleInsider forum mention problems with the Unity-based game, including glitches and freezes that appeared both during the High Sierra betas and after the public release.
A post on publisher Paradox Interactive's forum answering macOS user complaints about the game acknowledges the issues, advising it is being investigated. Current speculation indicates it is either an issue with Unity, linked to the existing High Sierra APFS problems, or a driver issue.
Firaxis and Aspyr title "Civilization V" is having issues with High Sierra APFS compatibility as well. The title, regardless of where purchased, either fails to launch or is crash-prone on APFS volumes. Some users have reported running the title from a HFS+ volume fixes the problem, with others getting no relief.
Numerous posts on the Steam forums raise concerns about games using Valve's Source engine, with reduced performance reported in titles including "Team Fortress 2," "Half-Life 2," and "Counter-Strike: Global Offensive." Aside from frame rate issues, some users also find that the Steam client itself is problematic following the move to High Sierra, with clients reporting they are not up to date, despite the user running the latest release of the software.
AppleInsider will continue to monitor this situation, and other compatibility issues that have been generated with APFS, and update accordingly.

The iPhone Team Lead for Unity Technologies Mantas Puida advises on the company forum that its High Sierra upgrade recommendation is "better postpone it." A previous version of the post advises that there were "some issues" with the beta 1 release of macOS 10.13, which also advised holding off on upgrading until issues were fixed.
One major issue raised during the beta releases was of disappearing assets in Project View, which was found to be an interoperability problem between Unity and APFS, Apple's new file system. While patches for releases 5.5.4, 5.6.3, 2017.1.1 and 2017.2.0 RC 1 and later do fix the disappearing asset bug, Unity confirms there will not be any fixes to version 5.4.x for High Sierra, and that affected users will either have to upgrade their project to Unity 5.5.x and later or keep using macOS 10.12.
During the High Sierra betas, a number of forum posters found they could still use Unity by installing the tool and project files onto a secondary drive formatted as Mac OS Extended (HFS Plus), though it did not work for everyone.
While Unity has largely solved that problem, the firm advises there are still some High Sierra-related bugs that need squashing. Users are unable to use Local Cache Server in Unity, as this will crash the whole operating system, with the current solution being to disable it for the moment, though the remote version is said to "work fine."
Monodevelop, a customized version of an open source development environment that ships with Unity, was reported by users to crash at startup when in High Sierra, an issue that has also been fixed in Unity patches. Another Monodevelop issue, where the software crashes when it is dragged between monitors, has yet to be solved.
Puida does offer some general advise relating to testing beta operating systems, suggesting "Please consider installing it to a separate partition to not interrupt your everyday workflow." The same advice could be extended to newer versions of operating systems and software as a whole, especially when used in mission critical or production systems.
Issues with game engines and operating system updates are usually felt not only by developers but also by players. Reports from players of "Cities: Skylines" on Reddit, Steam, and in the AppleInsider forum mention problems with the Unity-based game, including glitches and freezes that appeared both during the High Sierra betas and after the public release.
A post on publisher Paradox Interactive's forum answering macOS user complaints about the game acknowledges the issues, advising it is being investigated. Current speculation indicates it is either an issue with Unity, linked to the existing High Sierra APFS problems, or a driver issue.
Firaxis and Aspyr title "Civilization V" is having issues with High Sierra APFS compatibility as well. The title, regardless of where purchased, either fails to launch or is crash-prone on APFS volumes. Some users have reported running the title from a HFS+ volume fixes the problem, with others getting no relief.
Numerous posts on the Steam forums raise concerns about games using Valve's Source engine, with reduced performance reported in titles including "Team Fortress 2," "Half-Life 2," and "Counter-Strike: Global Offensive." Aside from frame rate issues, some users also find that the Steam client itself is problematic following the move to High Sierra, with clients reporting they are not up to date, despite the user running the latest release of the software.
AppleInsider will continue to monitor this situation, and other compatibility issues that have been generated with APFS, and update accordingly.
Comments
I'm confused by this statement. Do you think there are humans at Apple working to making bugs further away from zero?
First time I've ever had a problem with an OS install by Apple. Ever. I didn't hear any problems (outside of beta) about doing clean-installs with High Sierra, but warning to others not to do it just yet. It could be a problem specific to my machine/configuration but those considering it should wait. Obviously, Apple missed the QC train here.
Your computer is not a "critical operating system" and it was never designed to be that system. Period.
And that is a good thing, because otherwise, we would be buying computers costing 40-50k instead of 1k.
When consumer level PC fails, it fails and that is it. Sometimes computers can freeze because of the deadlock due to circular dependency issue and no one in the last 50 years decided to fix that. Why? Because it is f-ng cost prohibitive (both in terms of money and CPU cycles that would be wasted on that). So, instead of fixing it, the real solution is NOT TO FIX IT and rely instead on the fact that such events are extremely rare.
I have two iMacs, with my 2009 also being used as a test machine when Apple introduces a new OS. I will upgrade, clean-install, rinse-and-repeat to make sure there are no surprises so when it comes time to assist with Macs owned by others, it can be done quickly and with no downtime. I've lost track of how many times something like a bad Java release (I have to use it) just ruined the system configuration.
If you haven't done a clean-install since 2008, well then good for you. Many times I've had to choose between taking hours to clean someone's messed up system vs. just doing a clean-install. I don't see how you can claim it's a "voodoo incantation" since you haven't done one in almost 10 years. In my 10 years of using Macs, repairing them, troubleshooting, etc... I can say without a doubt that starting with a fresh system is the best way to eliminate many problems related to the issues others have done to their systems over the years. I'm very much an MacOS person vs. Windows (my Macs run both) MacOS is not 100% free from its own issues. They are just far more rare compared to Windows.
All my data is stored offline, or in a cloud service. My Macs could fail right now and I'm only a login-away at most on a new Mac to be right back where I was.
There ARE problems right now with APFS if one reads the boards. My specific problem today is not unique, the difference being that those problems were from the beta release whereas mine was the official earlier in the week. It's definitely related to APFS and the errors mean that APFS is not fully-baked yet. Since it's a new file system for Apple, I'm giving Apple some leeway since it's the first time I've ever had an OS issue. Nonetheless, people need to know to tread carefully when resetting their Mac back to factory.
While writing this post, I got my iMac back up and running. For those interested in actually learning something... the problem was resolved by creating a USB boot drive with High Sierra on it, and re-installing the OS via USB. Reinstalling High Sierra using the recovery partition on a clean APFS-formatted drive may (as it did for me) cause an invalid boot volume and crash your machine.
And even then, the first USB attempt did install the OS, but resulted in the spacebar key constantly repeating (not a keyboard issue) with no way to answer certain panel prompts before actually using the OS. The 2nd attempt after re-erasing the system drive worked fine.
So LKrupp... if you ever decide to do a clean-install to start fresh, you can thank people like us for taking the time to spread the knowledge.
Unfortunately it sometimes tends to come back and bite them in the ass.
Oh well, such is life.
APFS changes things. Sometimes programmers make assumptions when they code, and sometimes changes serve to remind why programmers shouldn't make assumptions. 3rd party apps will be fixed as time goes on. In the mean time, you're under no obligation to update to HS until you're sure your required apps are fully compatible. This is how it is for all OS updates.
Apple has a great page about creating a USB boot drive. A simply copy/paste into a terminal window was all it took.
https://support.apple.com/en-us/HT201372