By default, a DesignMerge print driver will omit a record's pages if a variable text frame oversets when the record is merged into the document. The session's Report will list the records that encountered an overset error. For example, here is a copy of a report where record number 2 and record number 3 encountered an overset error:

If a report indicates any errors were encountered, it can be helpful to save the report so you can reference the report later to see which pages were skipped by the print driver session (which pages were omitted from the output). To save the report, simply click the Save Report button.

Before committing to a DesignMerge print driver merge session, you can test your document for potential overset error conditions by running a Longest Line merge session, as described in Tutorial #2 (Postcard) in DesignMerge Documentation (available at Meadows Downloads). If you are having difficulty finding any oversets after running this session, see the I need help finding an overset text frame Knowledgebase Article.

If the Longest Line Test does not reveal any potential oversets, but a print driver merge session still encounters an overset error, you can run an Update Document merge session on a specific record to determine why this record is encountering an overset error. For example, if record number 2 encountered an overset error, run an Update Document merge session on Record 2 (as shown below):

You can then review the merged document to determine why the data for this record caused an overset. When determining why variable text overset, please note that Hyphenation and Justification settings may cause an overset for a particular record's data but not for the Longest Lines. 

There are several different methods that may be used to avoid an overset, as described in Tutorial #2 (Postcard) in DesignMerge Documentation:

• If the document's design allows, modify the formatting of the text or the size of the text frame to accommodate the variable text from any record in your data file.
• Use CopyFit with DesignMerge to fit oversetting variable text on-the-fly while merging.