By default, VTube wants file access to the C:\Users\Public\Documents\VTube folder to store configuration information.

Starting with Windows 10 build 16232, controlled folder access was introduced in Microsoft Defender Antivirus. Controlled folder access in Windows Security reviews the apps that can make changes to files in protected folders. Occasionally, the VTube installation and/or application will be identified as harmful.

If this is the case, then you might see an error like this during installation:

SOLUTION 1

You can add VTube to the list of safe or allowed apps to prevent them from being blocked. See this Microsoft article for how to add VTube to the safe list: https://learn.microsoft.com/en-us/defender-endpoint/customize-controlled-folders#allow-specific-apps-to-make-changes-to-controlled-folders

SOLUTION 2

Change the location of the configuration path.  See How to Change the VTube Config Folder