SQLDBA- What breaks with SQL server 2025

 

SQL Server 2025 known issues:

 With SQL Server 2025, Microsoft has introduced a major change in the OLE DB provider

·       MSOLEDBSQL 19 is now the default provider

The new provider enforces:

• Encrypt = TRUE (default)
• TrustServerCertificate = FALSE (default)
• Strict certificate chain validation

 

Impact: Connections will fail by default

 If our environment uses:

• Self-signed certificates
• Internal CA not trusted
• Or no encryption

 

Affected Components

This change impacts:

• Linked Servers
• Replication
• Log Shipping
• Applications using legacy connection strings

Earlier:

• SQLNCLI (old provider) ignored certificate validation issues

Now:

• MSOLEDBSQL 19 enforces strict security

 

✅ 1. Linked Servers Fail After Upgrade

Issue

• Linked servers fail due to mandatory encryption changes in SQL Server  2025
• If We configured linked servers using SQLNCLI (which was the default for years), they'll fail after upgrade with errors like:
• Errors: 7303, SSL trust, certificate issues [mssqltips.com], [learn.microsoft.com]

Msg 7303, Level 16, State 1

Cannot initialize the data source object of OLE DB provider "MSOLEDBSQL" for linked server "<linked server name>".

TCP Provider: The certificate chain was issued by an authority which is not trusted.

Msg 10054, Level 20, State 0 

A transport-level error occurred when receiving results from the server.

Msg 17832, Level 20, State 18

The login packet used to open the connection is structurally invalid; the connection has been closed.

[SQL Server]The target principal name is incorrect

Root Cause

SQL Server 2025 enforces :

• Encrypt = TRUE by default
• Strict TLS certificate validation

The fix is to either install proper certificates or reconfigure the linked server with TrustServerCertificate=yes — which defeats the security improvement but at least gets you running.

Fix Option 1 (Quick workaround) This bypasses certificate validation.  Not recommended for long-term use

EXEC sp_addlinkedserver

@server='MyServer',

@provider='MSOLEDBSQL',

@datasrc='ServerName',

@provstr='Encrypt=Yes;TrustServerCertificate=True';

 

Fix Option 2 (Best Practice – Recommended)

1. Install valid SSL certificate on SQL Server

 

 

 

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✅ 2. Replication Failure After Upgrade

Issue

Replication breaks due to encryption + certificate mismatch [learn.microsoft.com]

If publisher is SQL Server 2025 and your distributor is remote without a trusted certificate, replication will fail. You'll see:

 

OLE DB provider "MSOLEDBSQL19" for linked server "repl_distributor" returned message 

"Client unable to establish connection".

Msg -2146893019, Level 16, State 1

SSL Provider: The certificate chain was issued by an authority that is not trusted.

 

This hits transactional, snapshot, peer-to-peer, and merge replication. Replication Monitor in SSMS will also fail if it can't validate the certificate chain.

The workaround (if you can't deploy trusted certificates yet):

EXEC sp_changedistributor_property 

    @property = N'trust_distributor_certificate', 

    @value = N'yes';

 

Symptoms

• Replication monitor fails
• Publication changes fail

Fix

1. Configure trusted certificate on all nodes
2. Verify linked server between publisher & distributor
3. Restart SQL Agent
4. Reinitialize replication if required

 

 

✅ 3.  Full-Text Search

Issue

SQL Server 2025 introduces a new full-text index version. Existing catalogs stay on version 1 (unchanged since 2005) unless you manually upgrade them. After the engine upgrades, your full-text queries will fail:

Msg 30010, Level 16, State 2

An error has occurred during the full-text query. Common causes include: 

word-breaking errors or timeout, FDHOST permissions/ACL issues, 

service account missing privileges, malfunctioning IFilters...

 

Fix:

The fix is to rebuild your full-text indexes — or if you need to keep using the old version temporarily:

ALTER DATABASE SCOPED CONFIGURATION SET FULLTEXT_INDEX_VERSION = 1;

But version 1 is deprecated. This is a temporary workaround, not a long-term solution.

Full text search won’t index all of big plaintext documents whose size is larger than 25MB. The workaround is to edit the registry to remove the 25MB limit.

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✅ 4.  Database Mail  another bug 

Issue: After upgrading to SQL Server 2025, Database Mail may stop working mainly due to enforced TLS/SSL requirements, disabled configuration, or SMTP compatibility issues.

 

What happens to Database Mail after upgrade to SQL Server 2025

• ❌ Emails not sending
• ❌ SQL Agent alerts not working
• ❌ Error like:
• The SMTP server requires a secure connection
• ❌ Messages stuck in queue

 

 Step-by-step approach

Check if DB Mail is enabled- If the below query result output value 0 then enable it.

SELECT value_in_use FROM sys.configurations WHERE name = 'Database Mail XPs';

 

If 0 → enable it:

EXEC sp_configure 'show advanced options', 1;

RECONFIGURE;

 

EXEC sp_configure 'Database Mail XPs', 1;

RECONFIGURE;

 

Check service status

EXEC msdb.dbo.sysmail_help_status_sp;

If stopped:

EXEC msdb.dbo.sysmail_start_sp;

 

Fix SMTP security

EXEC msdb.dbo.sysmail_update_account_sp

    @account_name = 'YourAccount',

    @enable_ssl = 1,

    @port = 587;

 Use TLS-enabled SMTP (587 or 465)

 Not old port 25 (unless secured)

 

Check failures & queue

SELECT *  FROM msdb.dbo.sysmail_allitems ORDER BY send_request_date DESC;

SELECT * FROM msdb.dbo.sysmail_event_log ORDER BY log_date DESC;

 

 

Restart queue (if stuck)

EXEC msdb.dbo.sysmail_stop_sp;

EXEC msdb.dbo.sysmail_start_sp;

Validate network & permissions

Ensure:

• SQL Server service account has access to SMTP
• Firewall allows:
• Port 587 (recommended)

TEST email

EXEC msdb.dbo.sp_send_dbmail

    @profile_name = 'YourProfile',

    @recipients = 'your@email.com',

    @subject = 'Test Mail',

    @body = 'Test after upgrade';

 

 

✅ 5. SSIS / Visual Studio Issues

Issue

Old SSIS packages fail to open or upgrade

Fix

1. Install SSDT (SSIS extension) in VS 2026
2. Open project → upgrade packages
3. Replace deprecated providers (SQLNCLI → MSOLEDBSQL)
4. Reconfigure connection managers

 

 

✅ 6. Installation Errors (General)

Common Issues

• .NET missing
• WMI service failure
• OS patch missing

Fix Steps

1. Install:
• .NET 4.7.2+
2. Run:
3. sfc /scannow
4. Ensure WMI service is running
5. Apply Windows updates
6. Run installer as Administrator
   
   

✅ 7. Installation Failure (TLS 1.2 Disabled)

Issue

 SQL Server 2025 (17.x) installation fails if TLS 1.2 is disabled on the machine, including failover cluster instances.

Workaround: Enable TLS 1.2 on the machine before attempting to install SQL Server 2025 (17.x).  [learn.microsoft.com]

Fix (Step-by-step)

1. Open Registry Editor
2. Navigate to:
3. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols
4. Enabled TLS 1.2 (Client & Server = Enabled = 1)
5. Restart the server
6. Re-run SQL Server installation

After successfully installation of SQL Server 2025, we need to disable the TLS 1.2

7.       Turn it back off again.