I am running 2 identical iMacs in High Sierra and it is only 1 iMac that has this problem. I can connect to the DAM disk thru Adobe Experience Manager Desktop, but on several times throughout the day it disconnects on its own. It is also slow to load certain folders of assets. I have a gigabit internet connection so bandwidth is fine and most of the images in the DAM are small file sizes 500k to about 15MB. Don’t know if it could be a permission issue? Both Macs have their own passwords to log in and the preferences in AEM are the same too. Almost seems like the 1 Mac is like a slow running fawcett.