Veeam Upgrade: PostgreSQL SSPI Authentication Failed

Summary: After upgrading Veeam Backup & Replication, the PostgreSQL service may fail authentication for the postgres user when using SSPI (Windows integrated authentication).

Symptoms: During upgrade or Veeam service startup, the following error appears in logs:

FATAL: SSPI authentication failed for user "postgres"

Root Cause: The local Windows account running the upgrade (often a local Administrator) isn’t mapped to the postgres database role. Veeam’s installer attempts SSPI authentication via the Windows user, which PostgreSQL rejects unless explicitly mapped.

Solution: Add a mapping for the local admin account to the postgres role in the PostgreSQL ident map configuration file.

Steps:

1 - Open the file:

C:\Program Files\PostgreSQL\15\data\pg_ident.conf

2 - Append a line mapping your Windows user to the postgres role:

# Map local Windows admin to postgres role
map_admin   YOUR-PC\Administrator   postgres

3 - Verify that pg_hba.conf uses the matching map:

host    all    postgres    127.0.0.1/32    sspi    map=map_admin

4 - Restart the PostgreSQL service:

net stop postgresql-x64-15
net start postgresql-x64-15

Verification: Run the following test to confirm:

psql -U postgres -h localhost

You should connect without SSPI authentication errors.

Notes:

This typically happens on standalone or lab environments using local Windows accounts.
In domain environments, ensure the domain account is mapped instead.
File paths may differ depending on PostgreSQL version or Veeam installation directory.

References: