diff --git a/crates/ecstore/src/bucket/migration.rs b/crates/ecstore/src/bucket/migration.rs
index ae775a014..b5f587221 100644
--- a/crates/ecstore/src/bucket/migration.rs
+++ b/crates/ecstore/src/bucket/migration.rs
@@ -41,6 +41,7 @@ const IAM_FORMAT_FILE_PATH: &str = "config/iam/format.json";
 const IAM_USERS_PREFIX: &str = "config/iam/users/";
 const IAM_SERVICE_ACCOUNTS_PREFIX: &str = "config/iam/service-accounts/";
 const IAM_STS_PREFIX: &str = "config/iam/sts/";
+const MINIO_GO_ZERO_TIME: OffsetDateTime = time::macros::datetime!(0001-01-01 00:00 UTC);
 const IAM_GROUPS_PREFIX: &str = "config/iam/groups/";
 const IAM_POLICIES_PREFIX: &str = "config/iam/policies/";
 const IAM_POLICY_DB_PREFIX: &str = "config/iam/policydb/";
@@ -120,6 +121,15 @@ fn normalize_iam_config_blob(path: &str, data: &[u8]) -> std::result::Result<Opt
     if is_identity_path(path) {
         let mut identity: UserIdentity =
             serde_json::from_slice(data).map_err(|err| format!("parse IAM identity failed: {err}"))?;
+        if (path.starts_with(IAM_USERS_PREFIX) || path.starts_with(IAM_SERVICE_ACCOUNTS_PREFIX))
+            && identity
+                .credentials
+                .expiration
+                .as_ref()
+                .is_some_and(|expiration| *expiration == MINIO_GO_ZERO_TIME || *expiration == OffsetDateTime::UNIX_EPOCH)
+        {
+            identity.credentials.expiration = None;
+        }
         if identity.update_at.is_none() {
             identity.update_at = Some(OffsetDateTime::now_utc());
         }
@@ -441,7 +451,10 @@ mod tests {
     use crate::bucket::replication::{
         BucketReplicationResyncStatus, ReplicationMigrationBridge, ResyncStatusType, TargetReplicationResyncStatus,
     };
+    use rustfs_policy::auth::UserIdentity;
     use std::collections::HashMap;
+    use time::OffsetDateTime;
+    use time::format_description::well_known::Rfc3339;
 
     #[test]
     fn test_normalize_policy_mapping_legacy_timestamp_and_fields() {
@@ -493,6 +506,54 @@ mod tests {
         assert!(v.get("updatedAt").is_some(), "normalize should backfill updatedAt");
     }
 
+    #[test]
+    fn test_normalize_minio_permanent_credential_expiration() {
+        let cases = [
+            ("config/iam/users/alice/identity.json", "0001-01-01T00:00:00Z", true),
+            ("config/iam/users/alice/identity.json", "1970-01-01T00:00:00Z", true),
+            ("config/iam/service-accounts/svc/identity.json", "0001-01-01T00:00:00Z", true),
+            ("config/iam/service-accounts/svc/identity.json", "1970-01-01T00:00:00Z", true),
+            ("config/iam/service-accounts/svc/identity.json", "1970-01-01T00:00:00.000000001Z", false),
+            ("config/iam/sts/temp/identity.json", "0001-01-01T00:00:00Z", false),
+            ("config/iam/sts/temp/identity.json", "1970-01-01T00:00:00Z", false),
+            ("config/iam/users/alice/identity.json", "1969-12-31T23:59:59Z", false),
+            ("config/iam/users/alice/identity.json", "1970-01-01T00:00:00.000000001Z", false),
+            ("config/iam/users/alice/identity.json", "0001-01-01T00:00:00.000000001Z", false),
+            ("config/iam/users/alice/identity.json", "2030-01-01T00:00:00Z", false),
+        ];
+
+        for (path, expiration, should_clear) in cases {
+            let input = serde_json::json!({
+                "version": 1,
+                "credentials": {
+                    "accessKey": "test-access",
+                    "secretKey": "test-secret",
+                    "sessionToken": "test-session-token",
+                    "parentUser": "test-parent",
+                    "expiration": expiration,
+                }
+            });
+            let output = normalize_iam_config_blob(path, &serde_json::to_vec(&input).expect("serialize identity fixture"))
+                .expect("normalize should succeed")
+                .expect("identity path should be supported");
+            let identity: UserIdentity = serde_json::from_slice(&output).expect("deserialize normalized identity");
+
+            assert_eq!(identity.credentials.access_key, "test-access");
+            assert_eq!(identity.credentials.secret_key, "test-secret");
+            assert_eq!(identity.credentials.session_token, "test-session-token");
+            assert_eq!(identity.credentials.parent_user, "test-parent");
+            if should_clear {
+                assert_eq!(identity.credentials.expiration, None, "path: {path}, expiration: {expiration}");
+            } else {
+                assert_eq!(
+                    identity.credentials.expiration,
+                    Some(OffsetDateTime::parse(expiration, &Rfc3339).expect("parse expected expiration")),
+                    "path: {path}, expiration: {expiration}"
+                );
+            }
+        }
+    }
+
     #[test]
     fn test_normalize_bucket_meta_blob_resync_reencode() {
         let path = ".buckets/test/.replication/resync.bin";
diff --git a/crates/iam/tests/ecstore_test_compat/mod.rs b/crates/iam/tests/ecstore_test_compat/mod.rs
index bccd89f45..6569670e5 100644
--- a/crates/iam/tests/ecstore_test_compat/mod.rs
+++ b/crates/iam/tests/ecstore_test_compat/mod.rs
@@ -17,11 +17,11 @@
 //! All direct `rustfs_ecstore` facade imports used by tests in this crate
 //! must go through this module (architecture migration rule:
 //! `check_architecture_migration_rules.sh`). Keep the surface minimal —
-//! only what the tests actually need to build a temp-disk ECStore fixture
-//! and to flip the erasure setup type for lock-quorum fault injection.
+//! only what the tests actually need to run storage-backed IAM scenarios.
 
 #[allow(unused_imports)]
 pub(crate) mod fixture {
+    pub(crate) use rustfs_ecstore::api::bucket::migration::try_migrate_iam_config;
     pub(crate) use rustfs_ecstore::api::layout::SetupType;
 
     // `update_erasure_type` is a write-side global facade entry. Its use is
diff --git a/crates/iam/tests/minio_iam_migration_test.rs b/crates/iam/tests/minio_iam_migration_test.rs
new file mode 100644
index 000000000..265c3c20f
--- /dev/null
+++ b/crates/iam/tests/minio_iam_migration_test.rs
@@ -0,0 +1,182 @@
+// Copyright 2024 RustFS Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+mod ecstore_test_compat;
+
+use ecstore_test_compat::fixture::try_migrate_iam_config;
+use rustfs_credentials::{get_global_action_cred, init_global_action_credentials};
+use rustfs_iam::store::object::{
+    IAM_CONFIG_POLICY_DB_SERVICE_ACCOUNTS_PREFIX, IAM_CONFIG_POLICY_DB_USERS_PREFIX, IAM_CONFIG_SERVICE_ACCOUNTS_PREFIX,
+    IAM_CONFIG_USERS_PREFIX, ObjectStore,
+};
+use rustfs_iam::store::{Store, UserType};
+use rustfs_iam::utils::generate_jwt;
+use rustfs_policy::auth::UserIdentity;
+use serde_json::{Value, json};
+use std::collections::HashMap;
+
+const LEGACY_META_BUCKET: &str = ".minio.sys";
+const REGULAR_USER: &str = "minio-user";
+const SERVICE_ACCOUNT: &str = "minio-service-account";
+
+async fn seed_legacy_iam_object(env: &rustfs_test_utils::TestECStoreEnv, path: &str, value: &Value) {
+    env.put_object_bytes(
+        LEGACY_META_BUCKET,
+        path,
+        serde_json::to_vec(value).expect("legacy IAM object must serialize"),
+    )
+    .await;
+}
+
+fn assert_identity_fields(actual: &UserIdentity, expected: &Value) {
+    assert_eq!(
+        serde_json::to_value(actual).expect("loaded identity must serialize"),
+        *expected,
+        "migration must preserve every credential field except expiration",
+    );
+}
+
+async fn assert_identity_survives(
+    store: &ObjectStore,
+    identity_path: &str,
+    name: &str,
+    user_type: UserType,
+    source: &Value,
+    expected_policy: &Value,
+) {
+    let mut expected = source.clone();
+    expected["credentials"]["expiration"] = Value::Null;
+
+    let persisted: UserIdentity = store
+        .load_iam_config(identity_path)
+        .await
+        .expect("migrated identity must be persisted");
+    assert_identity_fields(&persisted, &expected);
+
+    for _ in 0..2 {
+        let actual = store
+            .load_user_identity(name, user_type)
+            .await
+            .expect("migrated permanent identity must remain loadable");
+        assert_identity_fields(&actual, &expected);
+    }
+
+    let mut mappings = HashMap::new();
+    store
+        .load_mapped_policy(name, user_type, false, &mut mappings)
+        .await
+        .expect("loading the identity must not delete its policy mapping");
+    let actual_policy = mappings.get(name).expect("migrated policy mapping must exist");
+    assert_eq!(
+        serde_json::to_value(actual_policy).expect("loaded policy mapping must serialize"),
+        *expected_policy,
+    );
+}
+
+#[tokio::test(flavor = "multi_thread")]
+async fn minio_permanent_identities_survive_migration_and_repeated_iam_loads() {
+    if get_global_action_cred().is_none() {
+        init_global_action_credentials(Some("MINIOMIGRATIONROOT".to_string()), Some("minio-migration-root-secret".to_string()))
+            .expect("root credentials must initialize for JWT validation");
+    }
+
+    let temp_dir = tempfile::TempDir::with_prefix("rustfs_minio_iam_migration_").expect("temp directory must be created");
+    let env = rustfs_test_utils::TestECStoreEnv::builder()
+        .base_dir(temp_dir.path())
+        .init_bucket_metadata(false)
+        .build()
+        .await;
+    for disk_path in &env.disk_paths {
+        tokio::fs::create_dir_all(disk_path.join(LEGACY_META_BUCKET))
+            .await
+            .expect("legacy metadata volume must be created");
+    }
+
+    let regular_source = json!({
+        "version": 1,
+        "credentials": {
+            "accessKey": REGULAR_USER,
+            "secretKey": "regular-user-secret",
+            "sessionToken": "",
+            "expiration": "0001-01-01T00:00:00Z",
+            "status": "on",
+            "parentUser": "regular-parent",
+            "groups": ["engineering", "operations"],
+            "claims": {"tenant": "alpha"},
+            "name": "MinIO regular user",
+            "description": "migrated regular identity"
+        },
+        "updatedAt": "2025-03-07T12:00:00Z"
+    });
+    let service_claims = json!({"sa-policy": "inherited-policy", "tenant": "alpha"});
+    let service_secret = "service-account-secret";
+    let service_source = json!({
+        "version": 1,
+        "credentials": {
+            "accessKey": SERVICE_ACCOUNT,
+            "secretKey": service_secret,
+            "sessionToken": generate_jwt(&service_claims, service_secret).expect("service-account JWT must be generated"),
+            "expiration": "1970-01-01T00:00:00Z",
+            "status": "on",
+            "parentUser": REGULAR_USER,
+            "groups": ["service-accounts"],
+            "claims": service_claims,
+            "name": "MinIO service account",
+            "description": "migrated service identity"
+        },
+        "updatedAt": "2025-03-07T12:00:00Z"
+    });
+    let regular_policy_source = json!({"version": 1, "policy": "readwrite", "updatedAt": "2025-03-07T12:00:00Z"});
+    let service_policy_source = json!({"version": 1, "policy": "readonly", "updatedAt": "2025-03-07T12:00:00Z"});
+
+    let regular_identity_path = format!("{}{REGULAR_USER}/identity.json", IAM_CONFIG_USERS_PREFIX.as_str());
+    let service_identity_path = format!("{}{SERVICE_ACCOUNT}/identity.json", IAM_CONFIG_SERVICE_ACCOUNTS_PREFIX.as_str());
+
+    seed_legacy_iam_object(&env, &regular_identity_path, &regular_source).await;
+    seed_legacy_iam_object(&env, &service_identity_path, &service_source).await;
+    seed_legacy_iam_object(
+        &env,
+        &format!("{}{REGULAR_USER}.json", IAM_CONFIG_POLICY_DB_USERS_PREFIX.as_str()),
+        &regular_policy_source,
+    )
+    .await;
+    seed_legacy_iam_object(
+        &env,
+        &format!("{}{SERVICE_ACCOUNT}.json", IAM_CONFIG_POLICY_DB_SERVICE_ACCOUNTS_PREFIX.as_str()),
+        &service_policy_source,
+    )
+    .await;
+
+    try_migrate_iam_config(env.ecstore.clone(), None).await;
+
+    let store = ObjectStore::new(env.ecstore);
+    assert_identity_survives(
+        &store,
+        &regular_identity_path,
+        REGULAR_USER,
+        UserType::Reg,
+        &regular_source,
+        &regular_policy_source,
+    )
+    .await;
+    assert_identity_survives(
+        &store,
+        &service_identity_path,
+        SERVICE_ACCOUNT,
+        UserType::Svc,
+        &service_source,
+        &service_policy_source,
+    )
+    .await;
+}