Is there anything else logged? In the build log? The jenkins log?

Thanks for your response Daniel.

Sadly, nothing out of the ordinary, which I do realise is very unhelpful. If you could suggest where I might look, I can scan the logs in more detail looking for specific tell-tale signs, but when I diff the logs from a build success with these build failures, aside from dates and paths etc, they are the same until the archive unit tests portion. What I can tell you is that the build artifacts are all correct and the unit tests run happily, it is only when they are to be archived the job fails.

I checked the folder which the unit tests write the XML files to, it is correct.
I checked all of the XMLs themselves, they are well formed.
I checked the path given for the archiving of the test results, it matches where they are

I downgraded Jenkins back to a previous version before JUnit was split out to a plugin, and the job script executes without issue. Happy to provide any further details in order to help track this issue down.

Which version of Jenkins did you downgrade to? Could you try pinpointing the version where it breaks? Is it really the one where the plugin was extracted?

What does the rest of the job configuration look like? Could you try setting up a minimal job that fails (and can be uploaded to allow others to reproduce the problem, i.e. only public or demo/dummy files), e.g. one where the XML file is set up in a batch step instead of compiling? Does it also happen on other Windows slaves? Does it happen when run on master?

Similar issue with 1.3 Junit plugin, Jenkins 1.586.
Reverting to Junit 1.1 solved it.

Recording test results
ERROR: Publisher hudson.tasks.junit.JUnitResultArchiver aborted due to exception
java.lang.NoClassDefFoundError: hudson/tasks/junit/JUnitParser$ParseResultCallable
	at hudson.tasks.junit.JUnitParser.parseResult(JUnitParser.java:90)
	at hudson.tasks.junit.JUnitResultArchiver.parse(JUnitResultArchiver.java:120)
	at hudson.tasks.junit.JUnitResultArchiver.perform(JUnitResultArchiver.java:137)
	at hudson.tasks.BuildStepCompatibilityLayer.perform(BuildStepCompatibilityLayer.java:74)
	at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20)
	at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:770)
	at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:734)
	at hudson.model.Build$BuildExecution.post2(Build.java:183)
	at hudson.model.AbstractBuild$AbstractBuildExecution.post(AbstractBuild.java:683)
	at hudson.model.Run.execute(Run.java:1784)
	at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
	at hudson.model.ResourceController.execute(ResourceController.java:89)
	at hudson.model.Executor.run(Executor.java:240)

Updated severity - actually, Junit plugin 1.3 is a complete blocker of the whole Jenkins instance.

To clarify, downgrading to 1.1 works? What about 1.2?

Note that JUnit plugin 1.3 is incompatible with Jenkins before 1.587. See comment to JENKINS-26060 for an explanation.

I see. Yes, probably version of core might be the issue. I did upgrade to the latest core, however that one contains another critical bug (related to losing slave restrictions in a job), so I had to revert.

I missed the upgrade to 1.2, so can't confirm.
I can see a similar https://issues.jenkins-ci.org/browse/JENKINS-25657