diff --git a/deploy/windows/installer/shopdb-install.ps1 b/deploy/windows/installer/shopdb-install.ps1
index 5f2b759..678fecf 100644
--- a/deploy/windows/installer/shopdb-install.ps1
+++ b/deploy/windows/installer/shopdb-install.ps1
@@ -786,8 +786,23 @@ data, STOP: you are about to destroy a database.
 CREATE DATABASE IF NOT EXISTS $DbName CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
 CREATE USER IF NOT EXISTS '$DbUser'@'localhost' IDENTIFIED BY '$appPass';
 CREATE USER IF NOT EXISTS '$DbUser'@'127.0.0.1' IDENTIFIED BY '$appPass';
+-- ::1 as well. On current Windows 'localhost' resolves to the IPv6 loopback
+-- FIRST, so an operator who types localhost instead of 127.0.0.1 arrives as
+-- '$DbUser'@'::1' - an account that did not exist, and MySQL answers "Access
+-- denied" naming a host the operator never typed.
+CREATE USER IF NOT EXISTS '$DbUser'@'::1' IDENTIFIED BY '$appPass';
+-- ALTER after CREATE, because CREATE USER IF NOT EXISTS is a NO-OP on an
+-- existing user and does NOT change its password. This stage generates a fresh
+-- password every run and overwrites .dbpass with it, so on any re-run after a
+-- partial failure the file held a password the server had never been told -
+-- "Access denied" while the operator was looking straight at the right file.
+-- ALTER makes the stored password and the handoff agree, every time.
+ALTER USER '$DbUser'@'localhost' IDENTIFIED BY '$appPass';
+ALTER USER '$DbUser'@'127.0.0.1' IDENTIFIED BY '$appPass';
+ALTER USER '$DbUser'@'::1' IDENTIFIED BY '$appPass';
 GRANT ALL PRIVILEGES ON $DbName.* TO '$DbUser'@'localhost';
 GRANT ALL PRIVILEGES ON $DbName.* TO '$DbUser'@'127.0.0.1';
+GRANT ALL PRIVILEGES ON $DbName.* TO '$DbUser'@'::1';
 ALTER USER 'root'@'localhost' IDENTIFIED BY '$rootPass';
 FLUSH PRIVILEGES;
 "@