Sometimes an error will occur when you uninstall older versions of MetaDefender Core v3 which use the MSI-based installer. When the uninstall process fails, you cannot install a new MetaDefender Core v3 instance, which means you cannot install a newer version of the product, nor can you re-install the version you had installed.
If you encountered a problem uninstalling MetaDefender Core v3 using the standard method, you will need to do a forced uninstall:
Stop all running Metadefender Core v3 processes by opening an elevated command prompt and entering the following commands:
net stop metascan
net stop metascan helper
Delete your MetaDefender Core directory.
Note: Usually this is located here: C:\Program Files (x86)\OPSWAT\MetaDefender Core X where "X" is your MetaDefender Core package (1, 4, 8, 12, 16 or 20). For example, if your package is MetaDefender Core 16, your directory would likely be C:\Program Files (x86)\OPSWAT\Metadefender Core 16.
Delete the MetaDefender Core registry: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\OPSWAT\Metascan
Remove MetaDefender Core from the MSI database using Microsoft Program Install and Uninstall.
Note: This is a special utility provided by Microsoft that removes either all Windows Installer information for a product or all products installed on a computer. Information about Microsoft Program Install and Uninstall (including download link and details) is located here.
After downloading the utility, please run it and follow the steps provided.
You have successfully force-uninstalled MetaDefender Core and can now install a new version of it.
This article applies to MetaDefender Core v3
This article was last updated on 2019-07-05