If you mean about "Software Management Solution", then you need to make suret, that missing managed endpoints in report have "Software Management Plug-in" installed.
1. Check this "All computers with installed Software Management Plug-in" filter and then check "All computers without installed Software Management Plug-in" filter ⇔ Compare results from both filters and determine whether these remaining missed computers have plug-in installed or not.
2. Did you check all required "Software Management Solution" reports to determine why targeted endpoint doesn't have this software installed? Maybe it fails to download software package?
3. Also take a look on what amount of license node you have for "Software Management Solution" product?
You can check this on "First Time Setup" portal page:
Thanks,
IP.