Known bugs in macOS Mojave 10.14: an incomplete summary

I will shortly be opening a separate article in which bad features, poor interface design, and problems with third-party apps, etc., will be recorded, and will add its link here. This article lists bugs which you and I have encountered in macOS Mojave itself.

Privacy protection (TCC) – bypass of privacy protection

Patrick Wardle has demonstrated that he can exploit a vulnerability in the new TCC system which enables its complete bypass. I will post further details of this when they are released. I suspect that this will be addressed in an early security update.

Privacy protection (TCC) – bypass of privacy protection

Jeff Johnson reports that he has discovered a different vulnerability in Mojave’s new privacy protection – separate from that of Patrick Wardle and not based on ssh – which he has reported to Apple.

Privacy protection (TCC) – ssh bypasses privacy protection

SentinelOne have reported that the remote shell ssh has, by default, no restrictions on accessing protected files and folders. This may be intentional, but as this feature is often enabled, many Macs may be vulnerable to remote attack on protected data.

The simple solution for the great majority of Macs is to disable Remote Login in the Sharing pane. However, if you need to retain ssh access, SentinelOne suggests connecting to that Mac using ssh, entering a protected folder such as ~/Library/Mail in order to add ssh or sshd-keygen-wrapper to the Full Disk Access pane, then toggling that on and off as required to control access to protected areas.

Hopefully Apple will provide a better solution in a future update to Mojave.

Slow boot – possible disk format problems

A small number of those upgrading to Mojave are suffering very slow boots following upgrading. These may appear to be related to the use of FileVault encryption and/or file system problems with the boot drive.

Unfortunately, no clear pattern is emerging but those affected should consider starting up from an unaffected drive or in Recovery mode and examining the affected drive using Disk Utility. In some cases, at least, it may be possible to reformat the boot drive correctly, reinstall, and return to normal startup. Thankfully these problems appear rare at present.

More common is an odd situation where many tasks, such as opening an app, become excruciatingly slow. It consider these in detail here: they should settle within 12-24 hours of starting to run Mojave, and require no action to resolve.

Install failures – possible disk format problems

A few reports are emerging of users who simply cannot get the Mojave installation to complete, typically encountering a fatal DiskManagement error -69854. These seem to be related to failure to convert Fusion Drives to APFS, and may also be associated with the use of FileVault encryption.

It should be possible to reformat the Fusion Drive (or boot SSD) in Recovery mode, or when booted from a USB bootable installer, and perform a clean install. If affected, it is worth contacting Apple Support, so that they can know how frequent this problem is.

Boot Camp – can’t install Windows on partition after Mojave

If you have an iMac 27-inch Late 2012 with a 3 TB hard disk and an existing Boot Camp partition, you must remove that partition using Boot Camp Assistant before you can install Mojave, according to an Apple support note. If you install Mojave with the Boot Camp partition still in place, you will then be unable to install Windows on it. Other models and configurations are not, apparently, affected.

iCloud Drive document sharing – versions erratic and unreliable

Although Apple has only recently documented that documents shared using iCloud Drive also share their previous versions, this may well have been present in High Sierra, and can work with Sierra systems too. However, the number of versions shown on different sharing systems is erratic and unreliable, and this feature can lose versions altogether.

Full details are in this article and followed up here. You should not rely on this feature working, particularly across different versions of macOS, and with iOS.

Thanks to Edoardo for first drawing my attention to this.

System Information – Legacy Software wrong and misleading

The information given about ‘legacy software’ in System Information is highly incomplete and misleading. Further details are here. Use 32-bitCheck (from Downloads above) instead.

Note that you cannot rely on Mojave to warn you of 32-bit software when you open an app: that only happens on the first occasion that an app is run after it has been downloaded from the internet. Existing installed apps generated no such warnings.

Dark Mode – QuickLook and other bugs

If you use an editor such as my DelightEd which is designed to produce RTF which ‘works’ in Dark as well as Light Mode, then QuickLook thumbnails and previews switch contained text to white in Dark Mode, but retain a white background. This renders the thumbnail/preview useless in Dark Mode.

A similar problem with Dark Mode exists when you use Control-Command-D to show the definition of a selected word: the popover window is semi-transparent, which makes text in custom dictionaries visible only when viewed over a window with a white background (such as in TextEdit). If the underlying window is dark grey, then that text is almost invisible.

These are described in more detail here. There don’t appear to be any workarounds for these, other than switching back to Light Mode.

Thanks to Artyom for drawing my attention to the second of these.

OpenGL – some apps open with black windows, or may hang

Several developers and others using apps which still rely on OpenGL have reported that their apps open with black windows, and some even freeze. This may be resolved by building them with Xcode 9.4.1 rather than 10, and there is further discussion here.

Thanks to @Deluxive for drawing my attention to this.

Screen Savers – Quartz Composer (.qtz) and some regular screensavers not supported

Mojave apparently no longer supports Quartz Composer (.qtz) screen savers, although it isn’t clear whether this applies to all or just most of them. I’m not sure that this is an actual bug, but it seems to have been a feature of all versions of Mojave including beta releases.

Some other screensavers with the extension .saver may also not work. It isn’t clear which, though, or why. Any which rely on OpenGL are prone to the bug listed above.

Thanks to @Deluxive for reminding me of this, and for providing further information.

Finder – incorrect column width

This can occur when using Finder windows which are set to column view. When switching folder in the view, the rightmost column being displayed has excessive width, filling the Finder window, its divider being placed incorrectly at the right edge of that window.


This long-standing but intermittent bug dates back to Mavericks if not earlier, and I have whinged about it here and here. It was also present in every version of El Capitan, Sierra and High Sierra. The only workaround is to select a different folder, then to select the correct folder again.

Sparkle updater – failure to download and install update

Many third-party apps use the Sparkle system to detect, download and install updates to third-party apps. At least one – that for BBEdit 12.1.6 – doesn’t work properly after upgrading to Mojave. It’s not yet clear whether this affects other apps too. The workaround is to visit the support website and download the new version of the app from there.

(Updated 13 October 2018 with System Information / Legacy Software.)