Contents of texts and folders are missing, blank

After installing Scrivener 3 for Windows a week ago, many of my older files are corrupted even before updating to the new format.
-outline folders and text are correct but the contents are missing.
-ditto for Scrivener 3 update format

-how can I recover the missing text contents

Please try disabling your antivirus software, then reinstall Scrivener 3.

All known instances of this problem involve security software deciding that Scrivener 3 is bad, and refusing to allow it to open files.