Save the document frequently when formatting a table so that you do not have to start back at the beginning if you regret a formatting step. Prepare complex tables as a separate document. Cut and paste them into the real document once the formatting is complete. It may help to work with View , Page Layout selected when formatting large tables. Word works more slowly but you get a better impression of the result.
Table disappears off bottom of a page Word can only split a table between rows.
Split deep rows. Column of numbers not properly aligned to a tab. Select all data cells in column. Check ruler and if tab does not show reset it. Check Format , Paragraph , Alignment is Left .