Apparently I forgot I had this particular problem and that I had a work-around: https://lists.samba.org/archive/samba/2023-November/247069.html But yeah...disjoining a computer, *and* deleting the computer account *and* deleting the record out of DNS is still causing problems on various servers I manage. Currently on version 4.17.12-Debian The Windows event log says the DNS server refused the registration: The system failed to register host (A or AAAA) resource records (RRs) for network adapter with settings: Adapter Name : {BC956BF1-F2DD-41C8-9ED1-7E5DA37859BC} Host Name : USGGZHMOFC04 Primary Domain Suffix : corp.cust.tld DNS server list : 10.142.28.240, 10.142.28.254, 10.100.100.100 Sent update to server : 10.142.28.240:53 IP Address(es) : 10.142.28.118 ...and the only logging apparently relevant out of Samba is: [2024/12/04 17:57:36.032964, 1] ../../source4/dns_server/dns_update.c:399(handle_one_update) discard_const(update): struct dns_res_rec name : 'USGGZHMOFC04.cust.tld' rr_type : DNS_QTYPE_A (0x1) rr_class : DNS_QCLASS_IN (0x1) ttl : 0x000004b0 (1200) length : 0x0004 (4) rdata : union dns_rdata(case 0x1) ipv4_record : 10.142.28.118 unexpected : DATA_BLOB length=0 One thing I noticed when I tried the work-around I mentioned in the thread was: dnsmgmt.msc did NOT show a record for the computer. "samba-tool dns query" did NOT show a record for the computer. "samba-tool computer" did NOT show an account for the computer. So I joined the computer, restarted, and ran "ipconfig /registerdns". No luck. Then I manually created the DNS entry for it and went to the Security tab to add the computer account, there was already an "unknown" account SID listed. Sorta like it was left-over from the previous entry that was deleted....so I removed it and added the newly-joined computer account. Basically re-using old names (even if you've deleted them everywhere) causes problems and there's definitely something buggy there. Since we have a very specific naming format that allows up to 99 machines in an office, names get re-used a few times per year when machines die and need to be replaced. I hate having to manually create them in DNS to work around this. ;) -A