Sometimes software updates can ruin your day. Catalina received an update for 10.15.7 and the last three OS received security updates as well. I’m disappointed to report that after these updates, SMB (Server Message Block) protocol is broken on all three of the recent OS (High Sierra, Mojave, and Catalina). Time Machine backups to my new TrueNAS server are suddenly broken and connections to my Windows-based server are broken as well.
Instability in Finder
Sometimes Finder will connect to these shares successfully using Go > Connect to Server… for a few minutes and sometimes it gives an error immediately. They also intermittently appear in the Network section of Finder. It might even have something to do with Finder losing the connection when the window goes to the foreground, but the behavior cannot be reproduced consistently.
Unhelpful AppleCare
The latest generation of AppleCare advisor seems to be rather unhelpful with issues related to connecting to servers. 5 of 6 advisors told me something like “macOS does not support connecting to servers” and that’s a troubling response. None of the advisors knew what SMB was without Googling it. The default reaction was to claim the issue was out of scope or blame the server.
Poor Documentation
Speaking to AppleCare triggered me to search for documentation. I’m quite shocked at how little documentation Apple provides on support for SMB. I remember when Final Cut added support for SMB shares, but now I notice a few of the links in that article are broken. Lack of documentation makes it easy to deny support for this sort of thing. This is an unfortunate situation for both customers and support staff.
Testing Big Sur
Eventually, a “Senior Advisor” acknowledged the issue could be with macOS, submitted logs from two Macs, and I waited a week for a response from “Engineers.” During the wait, I created a new APFS container and started testing SMB support in Big Sur. I tested SMB shares in a few of the different betas after they were released. Beta 7 disabled SMB entirely, Beta 8 enabled it again, skipped Beta 9, and then found Beta 10 had disabled SMB again. I shared this information with the “Senior Advisor” but eventually “Engineers” came back and said it wasn’t supported.
Does Apple care that it broke SMB? If this were Windows, it would be newsworthy, but on the Mac, there is little accountability when core functionality breaks. Will the final release of Big Sur fix SMB? We shall see at some undetermined point in the future.