Sometimes when using a custom theme that has not properly been updated and portal pages are hit for the first time after updating, the island size stored in the database can be off causing scrollbars, both horizontally and vertically.
A few steps are needed to remove the values to insert the correct sizes. First the theme must be fixed.
Navigate to the custom theme folder from the server or windows explorer if you have server access. The folder location is usually here, Drive:\inetpub\wwwroot\Production Portal\App_Themes\YourCustomFolderName
Open the CSS file under the theme folder. **To ensure updates are properly applied to the theme, make sure the CSS is named the same as the folder. ex)YourCustomFolderName.css
Compare this to the Default theme CSS to make sure no pieces are missing. Reference this article for more information regarding the changes with the 5.0+ updates.
Once the theme has been corrected, an easy script can remove those values from the database so that the next time the page is hit, the correct values are stored.
Take a backup of the framework database.
You will run the following script on the PwPageIslands table.
SET [Left] = NULL, [Top] = NULL, Width = NULL, Height = NULL
Refresh the portal cache or recycle the application pool.
Navigate to pages within the portal. The islands may take a second to fully render.