The Mac, and its operating systems, have for a long time been highly customizable. Apple’s range of options has been good, but much more limited than is available using third-party enhancements. These have allowed users to change their Mac’s appearance, and to enhance its usability and function.

For a substantial number of users, who have a vast range of medical and other conditions, such enhancements are not just fun things to do, but can determine how long they can use their Mac for, even whether they can use a Mac in the first place. Over the years Apple has accumulated some of the better ways of improving access, now mostly gathered in the Accessibility pane.

Those third-party developers who offer features which go beyond Apple’s options have not had an easy time. Back in the days of Apple’s Classic versions of Mac OS, adjusting some of the resources provided in the System files could often achieve a great deal. That was hideously insecure, of course, and with OS X developers and users have had to get used to more stringent limitations to what can be done.

A good example of this is with a rather ill-defined group of vestibular disorders. Many of us, at some time or another, will suffer from transient problems resulting from conditions affecting our inner ear and its neural connections. Most recover after a while, but there are plenty of people who, for periods of many years, remain sensitive to visual motion stimuli. In short, if there is too much movement on the screen, they suffer from motion illness.

Current releases of OS X El Capitan are rich in stimuli which, in those individuals, will cause motion illness. One of our leading Mac journalists, Craig Grannell, suffers from this, and finds vanilla El Capitan a serious challenge in use. He, and others with similar conditions, have found that a System extension, TotalSpaces2, is a great help. Craig has also tried to convince Apple that animation and motion effects should be under user control, so that he and others with vestibular disorders can use their Macs without fear of motion sickness.

Unusually for a company which listens so well to customers in its stores, Apple has done nothing to help those with vestibular disorders precipitated by animation and motion.

In days past, the answer would have been to keep using third-party extensions, from software developers who care better for their users. But this has now changed, with El Capitan’s security enhancement, SIP.

System Integrity Protection (SIP) does what should have been possible using permissions: it prevents users, even administrators, from tampering with the contents of key folders, including /System. This is really good, because it makes it very much harder for malware to get at the most sensitive and crucial parts of OS X.

Unfortunately, this SIP lockdown also prevents many third-party extensions from being installed, and that includes TotalSpaces2. The only way that you can now use those is to turn SIP off – a fiddly process which you have to perform at the command line after restarting in Recovery mode – and to leave it turned off, and your copy of OS X vulnerable to attack.

You could argue that SIP’s greatest benefit is in providing ‘herd immunity’: malware developers know that they have to work their way past SIP, so the few El Capitan users like Craig Grannell who are forced to disable it in order to use their Macs is unlikely to make much difference to the threat landscape. However true that might be, that is not the point. Every Mac which has to be used with SIP turned off is bad news for all of us, as it makes the reward for malware that much greater.

SIP lockdown has effectively killed the market for many such extensions, as an unintended consequence. For those extensions which were purely cosmetic or fun, this is no big deal. For someone desperate to stop their Mac’s windows from waggling and jiggling everywhere, it is disaster.

If Apple really cares about the users of OS X, it needs now to identify which third-party extensions cannot be implemented because of SIP, and to provide proper substitutes in the official release of OS X, perhaps as options in the Accessibility or other panes. Craig Grannell and thousands of other Mac users need one simple setting there, to turn motion effects off, but I am sure that there are others with different needs. This is in the true spirit of SIP and enhanced security: useful patches should be incorporated and made official.

If it does not, then it will discover that those who really suffer without the third-party extensions on which they are currently reliant, will abandon the Mac. OS X will be seen not as an empowering, friendly OS with the best interface in the business, but the result of design fascism: we think this is best, so like it or lump it.

As unintended as this consequence might be, unless Apple rises to the challenge, many users could find themselves looking for an operating system which they can tailor to their interface requirements. Let’s hope that Apple recognises this result of SIP, and does something about it, soon.