Error while merging existing PDF files (e.g. PdfLexer errors)

Although it is rare, occasionally you may experience problems when merging existing PDF files that are generated by software other than the Muhimbi PDF Converter, e.g. a Scanner application or other 3rd party solutions.

This may be an explicit merge operation issued using our software or a merge carried out because an InfoPath form is being converted that has PDF files as attachments (this invokes an internal merge operation in our software)

Although we do our best to be as compatible with as many PDF files as possible, the PDF Specification is interpreted slightly differently by the thousands of 3rd party applications that somehow export files in PDF format. As a result sometimes we run into problems.

Please carry out the following steps to verify that a merge operation is the cause of the problem:

  1. Copy all PDF files that are being merged together to a new folder.
  2. Launch the Muhimbi Diagnostics tool from the Windows Start menu.
  3. Enter the full path to the new folder in the Diagnostics tool and click the 'Merge Folder' button.
  4. If you get an error then there is a problem with one of the PDF files. Please send them, along with the logged error, to
Until we have verified and fixed the problem you can use the following workaround:
  1. Install a free or commercial PDF Printer solution such as Adobe Acrobat Pro or Bullzip PDF Printer.
  2. Open the problematic PDF file in a free PDF reader such as Adobe Acrobat or Foxit Reader.
  3. (Re)Print the file to the installed PDF Printer.
This will recreate the PDF file from scratch and remove all incompatibilities. The Muhimbi PDF Converter should now be able to merge it successfully.
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  • 0
    Johnson, Robert

    This isn't a valid solution for an automated process.  I am disappointed in the ability of Muhimbi to process existing PDF documents.  I think Muhimbi needs to use Adobe's SDK to process PDF documents rather than a proprietary application.

  • 0
    Jeroen Ritmeijer

    Hi Robert,

    Unfortunately the Acrobat SDK is not licensed or suitable for use on a server. 

    We work very hard to make our software as compatible as possible with the millions of files processed by it, but as PDF files are created by tens of thousands of different applications, which all generate slightly different PDF files, and many interpret the spec rather loosely, there is only so much we can do.

    Naturally whenever a problematic document is found we work with our customers to fix it or implement a workaround in our software.

    If you are experiencing a problem with a PDF file then please contact and we'd be happy to assist.

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