Recent versions of the DesignMerge software do not restrict the size of a DesignMerge print driver output file. However, you will encounter an error if the size exceeds the limitations of the operating system where you are running DesignMerge or if the size exceeds the amount of space that is available on your system. Additionally, you do not want to produce an output file that will be too large for your digital printer to process. 

You can control the size of the files that a DesignMerge print driver produces by separating the output into several files. This can be achieved by either merging ranges of records or by applying the print driver's Page Sets per Job feature. For more information, please see the DesignMerge print driver's manual, which is available in DesignMerge Documentation. 

If you are using DesignMerge for InDesign CS6 or earlier, DesignMerge print drivers will not produce an output file whose size exceeds 2 GB. If the size of an output file should exceed 2 GB, the print driver session will automatically end and the output file will not be saved or sent to your printer.