Error while installing worlds

RexyStorms​  Is your user folder inside a OneDrive folder?  I mean the Sims 3 folder in Documents > Electronic Arts, the one that has subfolders like Saves and Library and DCCache.  To find out, right-click the folder and select Properties > General, then look at the Location.

Which worlds did you install first and second?  It's possible that with two large worlds, the .ebc file the launcher is trying to create is too large even without any other content added.  Please also let me know whether you own and are planning to install any Store content that isn't a world.  Sometimes the order of installation can help here.