Apps which feature many and frequent changes in pointer type, such as browsers, therefore leak memory more quickly than those that change the pointer type less often. What is most likely is that, when the pointer has been customised using the settings in that pane, the memory used by the previous pointer isn’t freed following a change in pointer type. The leak appears to occur when the pointer type changes, for example from a standard arrow to an I-beam for the insertion of text. (Note that this interface device is termed a pointer, not a cursor, a common error.) The latter two items are one of the new features in Monterey, and have proved popular with users.

All Macs which appear to suffer this leak are using custom pointer controls in the Pointer tab of the Display, specifically a larger than normal Pointer size and custom outline and fill colours. The cause has now been isolated to a single group of settings in one preference pane, Accessibility. Neither was there any evidence of kernel or Mach zone memory leaks. What was perhaps most surprising was that some users were severely affected, but most users weren’t affected at all and could use the same apps for days without any significant change occurring in their memory use. At first this appeared confined to certain apps, including Firefox, Microsoft Word, and even Safari.

Soon after the release of macOS 12.0.1, reports appeared that some apps, notably Firefox, could suffer large and progressive memory leaks until they took 70 GB or more of app memory, and the Mac simply ran out. This article explains how it occurs, and how you can prevent it from happening on your Mac. Thanks to the work of the engineers at Mozilla, its cause has now been identified, and I’m very grateful to fujimidai1 who has pointed this out to me. You will no doubt have heard of the claimed memory leak in macOS Monterey 12.0.1.

Os x utilities ram