You might come across this type of warning being logged in your cd_transport.log or cd_core.log of the server where your Transport Service is running:
WARN JAXBUtil - State file removal failed: TRIDION_HOME\bin\transactions\tcm_0-1234-66560.state.xml
This warning is related to the Java version installed. If you are using Java 6 or higher, the jars jaxb-api.jar and jaxb-impl.jar are now embedded in the java version itself and no longer need to be available in the lib folder of your Tridion installation.
To remove this warning, check the TRIDION_HOME\lib folder and if you find these jars present, proceed to remove them. If you have a deployer(s) running in the same server, the same step will apply.
Let’s say you have removed the jars from the lib folder or they were already not there and you are still seeing this warning being logged. This could mean that the endorsed folder of a previous java version that required these jars (Java 5 and previous) is still present in the system. Navigate to the JAVA_HOME\lib\endorsed folder and if you find jaxb-api.jar and jaxb-impl.jar, proceed to remove them. After this step, restart your Tridion services and the warning should now be addressed!