I have a SQL Server 2019 Express installation. It was acting weird in that even though I had set it to mixed mode auth, I could not change the sa password (I know we shouldn't use this, but it's a requirement for an app) because my enterprise admin account was not a sysadmin.

So, I read a bunch of articles, but nothing helped, so since there was no data yet, I tried a reinstall, which didn't help and then uninstalled SQL Server, rebooted and reinstalled again.

This time, I could connect as sa or Windows auth using SSMS, but only if I append ,1433 to the server\db name in the SSMS connection window else I get the 26 error. I have read and checked all the fixes, the instance is not hidden, made the firewall rules, etc., but none of these things help.

I am tempted to delete the whole VM at this point and start over, but that's tedious.

  • 2
    By default Express is a named instances and runs on a dynamic port. Omitting the name would mean the default instance name. Perhaps before you used thr name MSSQLSERVER and this time forgot to change it from SQLEXPRESS?
    – Thom A
    Oct 26, 2023 at 17:27
  • It is the same for MSSQLSERVER. I have to use ,1433 login as well.
    – CBrianC
    Oct 26, 2023 at 18:26
  • I feel like there's something else going on here we're not being told. The default port is 1433, so omitting the port would direct the connection to that port.
    – Thom A
    Oct 26, 2023 at 18:35
  • error: 26 - Error Locating Server/Instance Specified? Instance names are resolved using SSRP (SQL Server Resolution Protocol) requests via the SQL Browser service listening on udp/1434 on the target machine. Is the SQL Browser service installed? Is the SQL Browser service running? Did you restart it after reinstalling (and renaming) the SQL Server instance? Oct 26, 2023 at 22:26


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