I am frustrated to the core. While fixing my Sql Server I've made the situation worse. Here is the problem: initially my master database was corrupted, so the MSSql service was not starting.

I tried to fix it following some instructions from the MSDN site, but I just could not, so I decided to uninstall Sql Server through Control Panel. Uninstalled every bit of sql from Control Panel, but the Sql Server still exists in my system.

Then I read somewhere to delete the Sql Server registry keys, I did the same. And now I cannot uninstall or even reinstall Sql Server on my machine.

I don't want to reinstall my Windows, can anyone help in here with a sure shot method of how to uninstall Sql Server and then reinstall it. Note that I have tried using the installation media also, but just couldn't install.

  • Try to restore your windows using Windows Restore. Then uninstall SQL using revo uninstaller.
    – Ricky
    Commented Jun 17, 2014 at 5:53
  • There is a 'Repair' option in the SQL Server installer under the 'Maintenance' tab. Try to repair your installation, the try to remove it. (When you 'cleaned' your registry manually, you did a backup, right? :) Restore it, then try to repair SQL Server if it can not repair now)
    – Pred
    Commented Jun 17, 2014 at 7:16
  • 1
    Perhaps follow this approach (should be similar): sqlblog.org/2010/10/25/… Commented Jun 17, 2014 at 12:56
  • am also facing the similar issue, for the purpose of installing sharepoint 2013, i installed sql 2012 rtm and now am trying to upgrade and its corupted. so i tried to remove the sql from control panel and restartad after uninstall. but when i installed it again, the prev.referencrs were still exists!!
    – samolpp2
    Commented Feb 2, 2017 at 5:51

2 Answers 2


My guess is since you have remamants of failed installation still present in your system that is why you cannot install the new instance. This can be fixed by deleting few registry keys related to SQL server. Follow below method , this method was given by Microsoft forum team and is recommended way to remove have helped me and forum users many time . If you have multiple instances below suggesstion would not work so dont use it.

First please refer to below Microsoft support link for what actions to follow before removing SQL Server instance. Its is for 2008 r2 but would be applicable to 2012 as well.


If still you face problem you might as well try below suggesstion which involves removing registry entries.

Note: Removing necessary registry entries might cause inconsistency so backup registry before doing changes.

•1. Uninstall the existing SQL Server and all the components from the add remove program.

•2. Backup the registry . Please read in details the MS link before proceeding.

•3. Delete the following keys using regedit:

◦--HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server


•4. Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall and delete all the sub-keys referencing SQL Server.

•5. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services and delete all the keys referencing SQL Server.

•6. Rename all the SQL Server folders in the computer.

•7. Reboot the machine.

If you dont find this useful or have confusion dont proceed. Open a case with Microsoft and allow them to have a look at your system. with my experience with many failed installation registry keys are left in corrupted state and only solution would be to remove them.But you need expert to fiddle with registry

PS: Above method was suggested in SQL server forum and works well.

Of course if you can please revert it would be helpful


just try to delete each and every files related to sql server 12 from:-

1. control panel
2. C:\Program Files (x86)\Microsoft SQL Server
3. From all registries also(open by using "win+r" then type "regedit" 

then just restart your system and check is it existing again or not?

  • There are several shared components and additional registry entries related to SQL Server. Removing them manually is a big pain.
    – Pred
    Commented Jun 17, 2014 at 7:10

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