Yes, it seems that in ARCHICAD 21 the "Save as File" button and the "Break Hotlink of Selected Modules" checkbox of the Hotlinked Module Settings Dialog have been removed from the Dialog and became two separate commands available both in the File menu and in the context menu of the Hotlinked Module.
However, the command works fine for me, I do not see any crashes when using it.
This may be file-specific, you should report it to your local reseller.
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