Today I needed to update our cube aggregation designs using the Usage-Based Optimisation Wizard but I got stuck on an error I;d not seen before

“Estimated Count or Partition Count must be specified for cube objects that require counting.”

Ok, not too helpful. I highlighted each dimension and clicked the “count” button for each one, but it still did not fix. I then looked a little closer and noticed that one of the dimensions had a red squiggle underneath it. I expanded the list and noticed that several of the attributes counts also had red squiggles underneath them, and that the counts were 0. I updated the counts to 1 and sure enough the squiggles disappeared. It's probably not a good idea to update each one to 1 but rather to the correct or at least the anticipated value.