Virtual Box Guest Edition will not update

Bokeh

Boss has two MacBook Airs sitting in his office, both running VB and Win 7. His Guest Edition shows 4.2.4R81684. On the other computer, running the same version of VB, the Guest Edition shows 4.18R75467. Says an update is available, but once you click on it, it does not update. I dont use VB, and these are his personal computers, so if anyone has an idea why one updated and one didnt, and how to get it to update, I am all ears.

Paperlantern

The last couple times I used VB on a mac i had to just remove the old VB instance and redownload the newest. It wont actually just "update" like a lot of apps can. Once the new one is in, just re-open the disk file.