Remove a partial installation of SQL Server

Original product version: SQL Server

Original KB number: 955404

Summary

A failed SQL Server installation or upgrade can leave an inactive SQL Server instance that blocks later Setup attempts and can cause Setup error 1639. This article describes how to use Setup logs and the installed features discovery report to identify and remove a partial installation without removing working instances. It also lists the diagnostic logs to collect if supported removal methods fail.

Symptoms

After a SQL Server installation or upgrade fails, a subsequent attempt to install or upgrade the same SQL Server version on the same computer might also fail. This issue is most commonly encountered after a failed in-place upgrade, where the failed Setup operation leaves a partially installed or inactive SQL Server instance on the computer. You can't reinstall SQL Server because Setup finds an existing partial instance.

You might see one or more of the following symptoms:

An instance appears as <InstanceName>.INACTIVE in the Installed SQL Server features discovery report.
Setup reports that the instance ID is already in use by an inactive SQL Server instance.
Setup returns error 1639 and the component log contains “MSINEWINSTANCE requires a new instance that is not installed.”
Summary.txt instructs you to uninstall one or more features before you rerun Setup.
A feature fails because a dependency failed, and the first failure in the logs points to an incomplete instance or unavailable installation source.

Cause

If SQL Server Setup fails during installation, a partially installed instance can remain on the computer. SQL Server Setup doesn't always roll back all of the changes made before the failure. When you run Setup again, Setup can detect the partially installed instance. This can prevent Setup from determining or creating the instance configuration required for the new installation.

The original installation failure can have many causes. For example, a prerequisite, installation source, Windows Installer package, or another setup component might have failed. Removing the partial installation doesn't resolve the original cause of the failure. You must correct the original failure before you retry Setup.

Prerequisites before you remove an inactive SQL Server instance

Before you begin, verify that you have usable backups of all user and system databases for every SQL Server instance on the computer.
Identify all working instances and record their instance names, instance IDs, editions, versions, and installed feature IDs so that you can distinguish them from the inactive instance.
Copy the latest SQL Server Setup log folder to a safe location. The default path is %ProgramFiles%\Microsoft SQL Server\<VersionNumber>\Setup Bootstrap\Log\<Timestamp>.
Use installation media for the same SQL Server major version that created the inactive instance, unless Summary.txt explicitly directs you to different media.
Run commands from an elevated Command Prompt. On a multi-instance server, validate the instance name, instance ID, and feature list before every removal command.
For a failover cluster instance, don't treat a cluster node as a stand-alone instance. Use the SQL Server failover cluster maintenance workflow and review the logs from the affected node.

Important

Don't delete SQL Server registry keys, services, folders, or files as a general cleanup method. Manual registry or file-system cleanup can remove shared components or damage working instances. If supported removal methods fail, collect logs and contact Microsoft Support.

Remove an inactive SQL Server instance

To remove an inactive SQL Server instance, complete the following steps in order. Stop at any step where the inactive instance no longer appears in the discovery report.

Review the setup result and identify the inactive instance

Open Summary.txt from the most recent failed setup attempt. If Summary.txt provides a command to remove the failed or inactive installation, use that command as the first removal method. Record the suggested uninstall command, instance name or instance ID, and the features listed in the command. Review Detail.txt and the first failing component log to confirm that the failure belongs to the inactive instance.

%ProgramFiles%\Microsoft SQL Server\<VersionNumber>\Setup Bootstrap\Log\<Timestamp>\Summary.txt
Run the uninstall command suggested by Setup

If Summary.txt provides an uninstall command, use that command to remove the partial installation.

Open an elevated Command Prompt and change to the directory that contains setup.exe on the appropriate SQL Server installation media.

For example:
```
cd /d "<Drive>:\<InstallationMediaFolder>"
```
Then run the exact command provided by Summary.txt.

For example:
```
setup.exe /Q /ACTION=UNINSTALL /INSTANCEID=<InstanceId> /FEATURES=<FeatureList>
```
This command is an example only. Don't substitute the instance ID or feature list with values from another installation or another computer. Use the values provided by Summary.txt for the failed installation.

Important

Verify the instance ID before running the command. On a computer with multiple SQL Server instances, running the command against the wrong instance can remove a working instance.

For more information, see Uninstall an Existing Instance of SQL Server (Setup).
Generate the installed features discovery report

Start SQL Server Installation Center from the matching media. Select Tools > Installed SQL Server features discovery report. Review the report and determine whether the partial installation is still listed as <InstanceName>.INACTIVE.

For example:
```
MSSQLSERVER.INACTIVE
```
If the inactive instance is no longer listed, verify that the working SQL Server instances and their expected features are still present. You can then proceed to the troubleshooting steps for the original Setup failure before retrying the installation.

If the inactive instance is still listed after running the uninstall command provided by Summary.txt, continue to the next step. Use the discovery XML to identify the Windows Installer products associated with the inactive instance and remove only those verified products.
Remove remaining Windows Installer products for the inactive instance

If the discovery report still lists the inactive instance after you run the uninstall command from Summary.txt, locate and open the discovery XML. Identify the entries associated with the inactive instance and record the ProductCode for each applicable feature. Before removing a product, verify that the ProductCode belongs to the inactive instance and not to a working SQL Server instance or a shared component.

ProductCode="{<ProductCodeGuid>}"

Run the following command from an elevated Command Prompt for each verified product code:
```
msiexec.exe /x {<ProductCodeGuid>}
```
Repeat the command for each ProductCode.

Caution

Remove only the ProductCode entries associated with the inactive instance. Don't bulk-uninstall products simply because their display name contains SQL Server. A computer can contain products and shared components that are required by working SQL Server instances.
Verify removal before retrying Setup
- Regenerate the Installed SQL Server features discovery report.
- Confirm that the inactive instance is no longer listed.
- Confirm that all working instances and their expected features are still listed.
- Review Programs and Features only as a secondary check; don't use product names alone to decide what to remove.
- Restart the computer if the removal operation requests it. Then rerun the original installation or upgrade from valid local or reliably accessible media.

Troubleshoot common removal scenarios and Setup errors

Scenario	What you might see	Recommended action
Inactive instance blocks setup	The discovery report shows `<InstanceName>.INACTIVE`, or Setup says the instance ID is already in use.	Follow the Remove an inactive SQL Server instance section. Use the uninstall command from `Summary.txt`, then remove only verified `ProductCode` entries that belong to the inactive instance.
Error 1639 / MSINEWINSTANCE	A component log says that a specified instance is already installed and `MSINEWINSTANCE` requires a new instance.	Correlate the product or transform with the inactive instance. Don't treat "invalid command line" as proof that user-entered setup syntax is the only cause.
Dependency fails with error 53 or network path not found	`Summary.txt` reports a dependency failure, and a component log reports that a source or network path is unavailable.	Restore access to the required source or use valid local media. Then remove the inactive instance if Setup created one. Retry only after the source problem is corrected.
Missing MSI or MSP in Windows Installer cache	Repair, patch, upgrade, or uninstall requests an MSI/MSP that can't be found, or a feature is unavailable for selection.	Use the Microsoft Learn procedure to restore missing Windows Installer cache files. Don't copy a file from another computer unless the documented validation confirms it's the exact required package.
Driver or runtime package is the first failure	The first failing package is an ODBC driver, OLE DB driver, or Visual C++ runtime package.	Repair or uninstall the affected dependency through its supported installer workflow, based on its MSI log and installed version. Don't remove all drivers by default.
Failover cluster instance	The failed operation involves an FCI node or clustered instance.	Use SQL Server Setup cluster maintenance actions, such as `Remove node` when applicable. Preserve cluster configuration and collect logs from each affected node.
Supported removal still fails	The `Summary.txt` uninstall command and verified `ProductCode` removal both fail, or the inactive entry remains.	Stop manual cleanup. Preserve Setup logs, discovery reports, MSI logs, and a system configuration snapshot, and contact Microsoft Support.

When to stop removal and collect logs

Stop the removal attempt if any of these conditions apply, and collect diagnostic logs and instance information before contacting Microsoft support.

You can't confidently map a ProductCode to the inactive instance.
The computer hosts other working SQL Server instances or shared features and the proposed removal could affect them.
The inactive instance belongs to a failover cluster and the normal cluster maintenance action fails.
The uninstall command fails repeatedly, Windows Installer reports missing source files, or msiexec removal fails.
The remaining option would require deleting registry keys, services, installer-cache files, or SQL Server folders manually.

Collect SQL Server diagnostic logs and instance information

Collect the following information before making additional changes to the computer:

The complete SQL Server Setup Bootstrap Log folder.
Summary.txt.
Detail.txt.
The feature-specific MSI log that's associated with the failure.
Any other relevant MSI logs.
The Installed SQL Server features discovery report in HTML and XML format.
The exact commands that you ran during the removal attempt.
The return codes reported by SQL Server Setup or Windows Installer.
Information about the SQL Server versions, instance names, instance IDs, editions, and installed features on the computer.

Note

SQL LogScout is a diagnostic collection tool. For SQL Server Setup or installation-related issues, use the Installation/Setup scenario so that the relevant setup logs and diagnostic information are collected. For more information, see Troubleshooting and diagnostic tools for SQL Server on-premises and hybrid scenarios.

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Last updated on 2026-10-21