Windows compiler and security requirements for NetBackup 9.1 and later installation and upgrade
NetBackup 9.1 and later for Windows uses the Visual Studio 2019 compiler and the Windows 10 Software Development Kit (SDK). The installation and the upgrade process use Microsoft redistributable utilities to install Visual Studio 2019 C++ run-time libraries on Windows hosts where they are not already installed. These utilities can fail or behave unexpectedly on hosts without all the security updates in place. Windows hosts must have all security updates in place before you install or upgrade to NetBackup 9.1 or later.
More information on the Microsoft redistributable utilities is available:
https://visualstudio.microsoft.com/downloads/
For further information about this issue, see either the NetBackup 9.1 Installation Guide or the NetBackup 9.1 Upgrade Guide.