OCR Processor Troubleshooting

29 Mar 20232 minutes to read

Exception Tesseract has not been initialized exception.
Reason The exception may occur if the tesseract binaries and tessdata files are unavailable on the provided path.
Solution1 Set proper tesseract binaries and tessdata folder with all files and inner folders. The tessdata folder name is case-sensitive and should not change.

  • C#
  • //TesseractBinaries - path of the folder tesseract binaries. 
    OCRProcessor processor = new OCRProcessor(@"TesseractBinaries/");
    //TessData - path of the folder containing the language pack
    processor.PerformOCR(lDoc, @"TessData/");
    Solution2 Ensure that your data file version is 3.02 since the OCR processor is built with the Tesseract version 3.02.
    Exception Exception has been thrown by the target of an invocation.
    Reason If the tesseract binaries are not in the required structure.
    Solution To resolve this exception, ensure the tesseract binaries are in the following structure.

    The tesseract binaries path is TesseractBinaries/Windows, and the assemblies should be in the following structure.

    Reason 1 An exception may occur due to missing or mismatched assemblies of the Tesseract binaries and Tesseract data from the OCR processor.
    Reason 2 An exception may occur due to the VC++ 2015 redistributable files missing in the machine where the OCR processor takes place.
    Solution Install the VC++ 2015 redistributable files in your machine to overcome an exception. So, please select both file and install it.
    Refer to the following screenshot:
    Visual C++ 2015 Redistributable file

    Please find the download link Visual C++ 2015 Redistributable file,
    Visual C++ 2015 Redistributable file
    Exception Can't be opened because the developer's identity cannot be confirmed.
    Reason This error may occur during the initial loading of the OCR processor in Mac environments.
    Solution To resolve this issue, refer this link for more details.
    Exception The OCR processor doesn't process languages other than English.
    Reason This issue may occur if the input image has other languages. The language and tessdata are unavailable for those languages.
    Solution The essential PDF supports all the languages the Tesseract engine supports in the OCR processor. The dictionary packs for the languages can be downloaded from the following online location:

    It is also mandatory to change the corresponding language code in the OCRProcessor.Settings.Language property.
    For example, to perform the optical character recognition in German, the property should be set as
    "processor.Settings.Language = "deu";"
    Issue Text does not recognize properly when performing OCR on a PDF document with low-quality images
    Reason The presence of low quality images in the input PDF document may be the cause of this issue.
    Solution By using the best tessdata, we can improve the OCR results. For more information,
    please refer to the links below.


    For better performance, kindly use the fast tessdata which is mentioned in below link,