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I have 2 iMac's which are networked and on the older one the number in brackets has steadily increased to 8. The newer one shows 2. The only practical issue this seems to create is that when the number changes on the one to which the printer is connected, I have to do a fresh search for the printer on the other one (printer sharing is on), and then reinstall the driver. Just a bit of a nuisance but I wonder what causes the number to increase.