After uninstallation the current or a previous version of DLP files are left behind.
When installing and uninstalling MSIexec, MSIexec 'remembers' the files that it creates. Any files that were created outside of this process may be left behind. This might include backups of existing files, custom certificate files, or files otherwise touched by a user outside of the workings of DLP.
Verify the uninstallation was otherwise complete(such as services removed).
Ensure you have no need for the remaining files such as for reinstallation.
You can safely then, manually delete the remaining files.