Update Manager not working?

[euphonious]

I have both an installation of R5 on my laptop and R6 on my desktop. I get many updates on R5 but very few on R6. For example, I have LibreOffice 4.4.5 on the laptop with R5 and version 4.4.3 on the R6 desktop. The update manager icon never pops on the lower right panel for my R6 installation. I occasionally run urpmi to get updates on my R6 installation but since both the update icon is missing and LibreOffice is at an older version in R6 compared to R5, I think something is wrong here. Any advice to resolve the issue?