where is memory in V 6.4.5.2 (x64)

I can’t find how to adjust memory in v 6.4.5.2 (64)

This setting was removed several releases ago.

If your goal is to prevent LO from overflowing your computer memory, use the quota system which ships with some OS’es (you didn’t mention yours). But be aware that such quota restriction may mean abnormal program termination when the quota is exceeded and a possible loss of document data.

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