Catalina: Apple wants to clear out Finder hangers when copying large amounts of data

Apple wants to fix a bug in macOS Catalina, which was apparently introduced by installing the latest version of the operating system. Under the current macOS version 10.15.4, the Finder may freeze when copying very large amounts of data, as users report – this did not happen up to 10.15.3. The problem becomes apparent when large files or several 100 GB projects are copied to RAID drives using the Mac Finder, for example in video post-production.

macOS 10.15.5 should provide a remedy

Apple has now fixed the bug in the beta of macOS Catalina 10.15.5. The problem is officially listed as resolved in the release notes of the latest Beta 4: Large file transfers to RAID drives should no longer cause the Finder to stop responding, the Mac manufacturer writes there.

The Finder hangers can be reproduced 100 percent, wrote the manufacturer OWC, who originally suspected that the problem was in the SoftRAID driver. After test runs, OWC then found that the bug was on the operating system side – and informed Apple. The storage specialist SoftRAID had already referred to Apple regarding the bug last month.

Workaround with side effects

OWC also has one Workaround for the bug releasedwhich, however, involves changing a setting in Mac's non-volatile RAM (NVRAM). This requires temporarily turning off Apple's System Integrity Protection (SIP) to adjust the setting. The procedure can also reduce read and write speeds by around 5 to 10 percent, warned OWC – but at least the finder would then no longer hang up when copying. On MacBook Pros with a T2 chip, the workaround can also result in no WLAN connection being established. Affected users should best wait for the system update at this time, it should appear soon.

(lbe)