According to my Google search it's something associated with MS Office.
However, Avast should be uninstalled according to the developer's instructions. You can check to see if you've removed all of the supporting files by downloading and running the shareware app Find Any File to search for any files with the application's or the developer's name in the file name. For Avast software you'd do the following search(es):
1 - Name contains avast
Any files that are found can be dragged from the search results window to the Desktop or Trash bin in the Dock for deletion.
FAF can search areas that Spotlight can't like invisible folders, system folders and packages.
You can try turning it off in preferences and see how your MS Office apps respond.
Where and how often do you get the userinit.sh notification?