VRoid Studio might fail to start due to the presence of antivirus software on your computer.
Please try the following methods.
① Change your PC's security (firewall) settings
・Windows
Reference (external website)：http://faq.buffalo.jp/app/answers/detail/a_id/792
・Mac
Reference (external website)：https://support.apple.com/ja-jp/HT202491
② Remove VRoid Studio from the monitoring target of your antivirus.
Note:
・Please refer to the instructions of your PC regarding security settings and antivirus software operation.
・Please be careful not to change the settings or unblock any zip files of unknown origin.
Also, please make sure you're using the latest version of VRoid Studio.
You can download the latest version here.