Error messages and troubleshooting This section contains information about problems that you might encounter and how to resolve them. Prerequisite softwareThe prerequisite software that the DITA-OT requires depends on the types of transformations that you want to use.DITA-OT error messagesThis topic lists each error message generated by the toolkit and provides additional information that might be helpful in understanding and resolving the error condition. If your toolkit installation includes custom plug-ins that define additional messages, you can add to this list by rebuilding the DITA-OT documentation.Other error messagesIn addition to error messages generated by the DITA Open Toolkit, you might also encounter error messages generated by Java or other tools.Log filesWhen you run the DITA-OT, key information is logged on the screen. This information can also be written to a log file. If you encounter a problem, you can analyze this information to determine the source of the problem and then take action to resolve it.Accessing help for the dita commandYou can access a list of supported parameters for the dita command by passing the --help option on the command line.Checking the DITA-OT versionYou can determine the version of the DITA Open Toolkit from a command prompt.Enabling debug modeWhen the debug mode is enabled, additional diagnostic information is written to the log file. This information, which includes environment variables and stack trace data, can help you determine the root cause of a problem.Increasing Java memory allocationIf you are working with large documents with extensive metadata or key references, you will need to increase the memory allocation for the Java process. You can do this from the command-line prompt for a specific session, or you can increase the value of the ANT_OPTS environment variable.Reducing processing timeSeveral configuration changes can significantly reduce DITA-OT processing time.Parent topic: DITA Open Toolkit User Guide