Hi, this sucks.
I have been scouring Mod The Sims 3 forums all morning. I downloaded Delphy's dashboard tool which seems like a fantastic solution to this problem. ( You can find it here: http://www.modthesims.info/download.php?p=3512549&posted=1#post3512549
I ran it and it found a few corrupt files and Sims 2 packages, some of which were disabled and some of which were fixed, which was great. However, even before downloading my giant haul of custom content I was experiencing the blue squares of death in my neighborhood. Empty lots show up fine, some very simply residential lots show up, none of my parks are showing up and some community lots like town square are completely blue or missing entirely. This is in Sunset Valley.
Houses that I have built, (like the one I've spent nearly 50 hours creating) are missing entirely. There's no icon or anything whenever I hover over the lot and they are unclickable. Occasionally after exiting CAS or build/buy ode on another lot will the blank lots appear as blue squares.
I know many others have experienced this issue after installing World Adventures. I have no expansion packs installed though and I can't seem to find a solution to my issue. I would love to discuss this with other people who are having the same issue, as I am not terribly computer savvy and see if we can't come up with a solution together seeing as EA seems to have neglected this issue entirely. >.>
I am hesitant to upgrade to the newest patch for obvious reasons and am currently running version 1.18.9.009001 with no expansion packs.