In regards to Windows: software scanning mimics Add/Remove Programs. If the software package is not listed in Add/Remove Programs, you will need to use
file or
registry scanning to detect it.
In regards to Linux: Lansweeper will run one of the commands below to retrieve software records. If a software package is not in the command output, it will not be detected. If this doesn't explain the behavior you are seeing, we will continue troubleshooting via email. I notice you sent us an email as well. Keep in mind that custom scanning is not currently available for Linux computers, so detecting software not included in the output of the commands below will not be possible.
dpkg
equery
lslpp
pkg_info
pkginfo
rpm
swlist