Refresh error / Exceed maximum page size of the storage object (65528 bytes)

After extensive search, we came to the conclusion, that the dataset had too many columns. The number of rows wasn't an issue—it was all about the columns. This, combined with the architecture of the dataset, caused the problem.

We are loading multiple tables with this structure:

 
The dataset architecture used queries for each of these tables. In the second step, we merged all these queries into a master table and repivoted all the columns from the matrix format into one table with only four columns:

When reloading the OLAP Cube, the error message popped up.

How did we fix the issue?

We repivoted each table before merging them into the master table. By doing this, we prevented the OLAP Cube from loading an excessive number of columns.

An alternative, maybe easier approach is - if the multiple tables are being merged into one table and repivoted (like in the example above) - deactivating the single Tables/queries from being loaded into the dataset also helps. The data is still being considered in the master table, but the single Tables/queries are spared from entering the OLAP Cube.

Hope that helps someone.