The dialog box should mention which software or driver is missing under the Missing Components section. To get rid of this, you will need to download the software that is missing and activate it, if necessary.
For example, if you are running a project in LabVIEW using 64-bit software, you may see the error Missing NI Module, Toolkit, or Driver: NI LabVIEW Database connectivity for the following VIs. LabVIEW Database Connectivity Toolkit is only compatible with LabVIEW Base, Full, or Professional Development System (32-bit), so it will not run with LabVIEW using 64-bit software. You can download the 32-bit version from here.