Robin,

A somewhat new feature of the Windows VM (and maybe only Windows) is the ability to allocate more virtual memory to grow the Squeak heap when needed. I can't tell you exactly how this may alter things from the Mac that I use, but what I see in addition to the unresponsiveness is that there is a file being written in the Squeak folder 'LowSpaceDebug.log'. Given that the entire stack is being written to this file, things may take a while. This file, excerpted below, shows a nearly endless repetition due to some cyclic references. The #storeString family of methods are rather old, fairly simple and do not handle cyclic structures. They are useful for simple things like arrays of integers and strings, but for more complex objects, what you may be looking for are ReferenceStream and SmartRefStream - these will deal with cyclic structures.

Cheers,
Bob

[snip]
TextMorph(Object)>>storeOn:
WriteStream>>store:
Array(ArrayedCollection)>>storeElementsFrom:to:on:
Array(ArrayedCollection)>>storeOn:
Array>>storeOn:
WriteStream>>store:
PasteUpMorph(Object)>>storeOn:
WriteStream>>store:
TextMorph(Object)>>storeOn:
WriteStream>>store:
Array(ArrayedCollection)>>storeElementsFrom:to:on:
Array(ArrayedCollection)>>storeOn:
Array>>storeOn:
WriteStream>>store:
PasteUpMorph(Object)>>storeOn:
WriteStream>>store:
TextMorph(Object)>>storeOn:
WriteStream>>store:
Array(ArrayedCollection)>>storeElementsFrom:to:on:
Array(ArrayedCollection)>>storeOn:
Array>>storeOn:
[snip]