I'm seeing the following in 1.3 and a 1.4 build from a couple of weeks ago: ============== ***System error handling failed*** [...] ReadStream(Object)>>shouldNotImplement ReadStream>>nextPut: EncoderForV3PlusClosures(Encoder)>>allLiterals MethodNode>>generate: MethodNode>>generate MethodNode>>schematicTempNamesString CompiledMethod>>decompileWithTemps Decompiler>>decompileBlock: =============== Since the debugger can't open, I don't have much more information than this. Looking at the decompiler, it's clear that it sometimes initializes the Encoder's literalStream to a ReadStream, although that stream is never read from, only written to. Changing the initialization to a WriteStream just sends the system into infinite recursion. Any ideas on how to debug this? Thanks, -Martin