The TrueNAS SCALE machine that runs my SMB shares was in trouble. Windows clients had stopped seeing the shares reliably — intermittent at first, then completely. When I dropped to the shell to check, systemctl status smb returned something worse than a failed service: it returned a service that no longer existed. Same for nmb. Same for winbind. The service wrappers were gone.
Samba's binaries were still there. The actual smbd and nmbd executables under /usr/sbin were untouched. But the systemd units that normally wrap them, and the TrueNAS middleware that manages both, had lost too much of themselves to be repaired by unit regeneration or middleware restart. Something at the service-layer wiring had broken beyond in-place fix.
The recovery answer, once I stopped trying to patch it, was a fresh ISO reinstall and a pool reimport. That got the service layer back. What it didn't do — what nobody had warned me it wouldn't do — was fix Windows authentication or fix ACL permissions on the imported datasets. Two things I'd inherited from the reinstall broke SMB access in ways that had nothing to do with SMB itself.
This piece is the story of those two things. The SID mismatch that made Windows reject correct credentials. The missing default ACL entries that blocked recursive permission repair. And the fix sequence that restored SMB access to what it had been before the service layer disappeared.
