Repair/Remove/Install processes for SQL Server 2012 Express get stuck or hung

Try sbEnable=1

This advice from TechNet worked for me:

Following Registry-Key must be set to 1[...]:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\AppCompat\sbEnable = 1

In my case that registry directory did not exist at all. And the uninstall was STILL stuck at that location for several (less than 10) minutes. But eventually it continued and finished.

Here's what worked for me.

Solution 1:
- Stop the "SQL Server (SQLEXPRESS)" & "SQL Server VSS Writer" services and set their Startup Type to "Manual".
- Restart the PC.
- Run the repair process.
- Change the Startup Type back to "Automatic" and restart the services.

Solution 2:
- Stop the "SQL Server (SQLEXPRESS)" & "SQL Server VSS Writer" services and set their Startup Type to "Disabled".
- Restart the PC.
- Run the Remove process to uninstall SQL Server Express entirely (instance + shared components).
- Restart the PC again.
- [Optional] Run your favorite registry cleaner such as CCleaner.
- Install SQL Server Express (unless your goal was just to uninstall it).

NOTE: In the Solution 2 scenario, I tried the Repair process after the 1st PC restart, but it got stuck at step SqlEngineConfigAction_repair_validation_Cpu64.

In my case the reason for the uninstaller getting stuck at SqlEngineConfigAction_repair_validation_Cpu64 were invalid file paths in the SQL server's system tables.

To correct this, allowing uninstallation, this worked for me:

1) Set service to use local account (Start -> Local Services -> SQL-Server->Properties -> Log on -> Local System acccount)

2) Follow the steps here: https://social.technet.microsoft.com/wiki/contents/articles/31786.sql-server-not-starting-after-fresh-installation.aspx

3) Retry uninstalling.

In case the above link becomes unavailable, here's a short summary:

• Start the SQL server service in recovery mode: NET START MSSQL$SQLEXPRESS /f /T3608
• Connect to server: SQLCMD -S .\SQLEXPRESS
• List the files referenced in system table: SELECT name, physical_name, state_desc FROM sys.master_files ORDER BY database_id; (go)
• Wherever the file path points to something invalid (like a missing drive), adjust it, using this: ALTER DATABASE model MODIFY FILE ( NAME = modeldev, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL13.SQLEXPRESS01\MSSQL\DATA\model.mdf'); (go) Note that the files have different NAMEs and different extensions (.mdf, .ldf)
• Exit sql server (exit)
• Shut down the service NET STOP MSSQL$SQLEXPRESS