We just recently switched from Unity 2018.4.4f1 to Unity 2019.2.0f1 and noticed that the macOS build output is subtly different and causes the Steam client to throw up an "OS Error 4294956486" when launching our game (SimpleRockets 2). The same error is also thrown by Finder when double-clicking on the app in /Steam/steamapps/common/SimpleRockets2/SimpleRockets2.app. Outputting /var/log/system.log shows this line: (com.jundroo.SimpleRockets2.8148): Could not find and/or execute program specified by service: 2: No such file or directory: /Users/jundroo/Library/Application Support/Steam/steamapps/common/SimpleRockets2/SimpleRockets2.app/Contents/MacOS/SimpleRockets2 The problem is that the name of the app's Unix executable has been changed to include spaces, whereas in previous versions of Unity it did not. In previous versions of Unity this resulted in building a Unix executable at this path: SimpleRockets2.app/Contents/MacOS/SimpleRockets2 With Unity 2019.2.0f, it now builds to the same path, but includes a space: SimpleRockets2.app/Contents/MacOS/SimpleRockets 2 It may do this with other versions of Unity, but I have only tested with Unity 2019.2.0f1 and Unity 2019.2.3f1 and they both include the space. This seems to be a mixture of how Steam updates apps in-place which appears to throw off macOS since the name of the Unix exec has changed and macOS is still looking for the old path. Uninstalling and re-installing via the Steam client seems to fix the issue. Also, moving the SimpleRockets2.app to a different path and then moving it right back seems to fix the issue without requiring a re-install. Unfortunately there's no way to inform players about this and after they update they will be stuck with this OS error until they run across a forum post on how to fix the issue. Has anyone else seen this issue or have any suggestions on how to change Unity to build the Unix executable to the same path as it did in Unity 2018.4.4. I'm using macOS Mojave 10.14.5 (18F132) and I have not tested with other versions of macOS.