Image preview and thumbnail does not work


Preview and thumbnails of images does not work in a Windows system.

This also happens if you try to use the convert service from webservice API.


To generate preview and thumbnails of images, an external program convert.exe (located at $TOMCAT_HOME/bin) is used. In this case, this program fails because it needs a 32 bits DLL file. You will see an error message in openkm.log like this one:

2016-08-29 10:50:27,546 [http-bio-] WARN com.openkm.util.ExecutionUtils - Abnormal program termination: -1073741515
2016-08-29 10:50:27,547 [http-bio-] WARN com.openkm.util.ExecutionUtils - CommandLine: [C:/openkm-dev/tomcat-7.0.27/bin/convert.exe, -thumbnail, 280x280>, -background, white, -flatten, C:\Users\OpenKM\AppData\Local\Temp\okm4569534357915233684.jpg, C:\openkm-dev\tomcat-7.0.27\repository\cache\thumbnail\properties\3f4e4f74-e51c-46c3-9276-012e034a1a7f.png]
2016-08-29 10:50:27,547 [http-bio-] WARN com.openkm.util.ExecutionUtils - STDERR:
2016-08-29 10:50:27,547 [http-bio-] WARN com.openkm.util.ExecutionUtils - STDOUT:
2016-08-29 10:50:27,551 [http-bio-] ERROR c.o.s.frontend.ConverterServlet -


Try to run a conversion from command line and you would see this error dialog:

After seen the previous error dump, try to execute the program from command line. To do this go to $TOMCAT_HOME/bin and execute the following command:

convert -thumbnail 280x280> -background white -flatten test.jpg test.png

Where test.jpg shoud be a valid image. The execution of the command will show the following error:

vcomp100.dll is missing


OpenKM by default it comes with convert.exe 32 bits version. In almost cases, althought you be in 64 bits computer, will be better installing 32 bits redistributable package or both.

To fix the error it is necesarry to install the required DLL. To do this download and install Microsoft Visual C++ 2010 Redistributable Package:





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Applies to

  • Frontend
  • Webservices



  • AllVersions