Hi John - Because Rehearsal Live Share is so new, and has changed so rapidly over its young life, we have not yet made it onto any Windows antivirus whitelists. We have submitted to Microsoft for review. We're still waiting on that. Also because there are so many third party antivirus programs on Windows, it may be awhile before we can avoid these erroneous warnings. (This process is a lot easier on the MacOS/iOS side, where we able to secure Apple's approval from the beginning.) For what it's worth you can inspect our code-signed credentials in the Properties section of the application. Until we get the official Microsoft seal of approval, you can still run the installer by selecting some form of "More Info" and "Run Anyway" in your security program. Below are some screenshot examples from Windows Defender.