As you may be aware, Windows Installer (MSI) doesn't work by default in Windows Safe Mode. This can be very frustrating because you may have installed an app in normal mode which later prevents the OS from starting. But it can't be removed from safe mode because the Windows Installer service doesn't start in Safe Mode. Here is a simple workaround which will allow you to start the Windows Installer service in Safe Mode.
Yesterday, I was repairing a PC for a friend. After an improper shutdown, his antivirus software started to prevent the operating system from booting normally. Once the Desktop appeared, the OS was crashing with an error code that said BAD_POOL_HEADER (BSoD). It took me some time to figure out that it was his antivirus, but once I found it, I faced the issue that it was not removable in Safe mode!
If you try to uninstall an app which was installed from an MSI package in safe mode, you will get the following error:
The Windows Installer Service could not be accessed. This can occur if the Windows Installer is not correctly installed. Contact your support personnel for assistance.
Here is how to avoid this issue.
To enable Windows Installer in Safe Mode, do the following.
- Open the Registry Editor app.
- Go to the following Registry key.
See how to go to a Registry key with one click.
- Create a new subkey here named "MSIServer".
- In the right pane, set the default value of the MSIServer key to "Service" as shown below.This will enable Windows Installer in the regular Safe Mode (without network support).
- Now, repeat the same under the key
This will enable Windows Installer in Safe Mode with Network support. See the screenshot below.
- Now, open the command prompt and type:
net start msiserver
This will instantly activate the Windows Installer service.
Now, you can uninstall your MSI app also in Safe Mode!
This trick works in all modern Windows versions including Windows 10, Windows 8 and Windows 7.
To save your time, you can use Winaero Tweaker to enable Windows Installer in Safe mode. Turn on the option "Behavior\Windows Installer in Safe Mode".
You can download Winaero Tweaker here:
Alternatively, you can download the following Registry files.
The undo tweak is included.