A further observationthat makes things seem far worse: the error is dependent on the content!
The document in question has several chapters, each in a separate file. Dependent on the combination of files included, the error does or does not show up. Sofar I cannot find a pattern linked to the error. Making a minimal example proved impossible, alas.

Hans van der meer

On 27 Dec 2015, at 13:19, dr. Hans van der Meer <havdmeer@ziggo.nl> wrote:

A document that runs fine under
   ConTeXt  ver: 2015.10.09 21:28 MKIV beta  fmt: 2015.10.11  int: english/english
suddenly doesn't under
  ConTeXt  ver: 2015.12.22 10:50 MKIV beta  fmt: 2015.12.27  int: english/english
mtx-context     | fatal error: no return code, message: luatex: execution interrupted

Loaded this beta today.
The previous beta runs ok, the new beta gives the error. The pdf produced in the latter seems at fault.
Anyone knows how this error can occur?

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