This message was driving me nuts for the longest time thinking it was a Favorite folder linking back to the culprit server on the sidebar of a Finder window but that was not the case – I removed all aliases linking back to the server and still no glory.
This thread saved me from going completely mad: https://discussions.apple.com/thread/7583341
… and thankfully my issues were solved in Step 1. There are 13 Steps provided by one of the users and you can imagine my frustration scrolling down the long list thinking “I’m never going to fix this”…
This is what worked for me:
If you get the alert right after you log in, it’s probably caused by one of your login items or by software that otherwise loads at startup or login. Common offenders are “1Password” and “Adobe Resource Synchronizer,” but there are many others. Select the Login Items tab in the Users & Groups pane of System Preferences. Delete any suspicious items. If you’re not sure which ones to delete, double-click each to test it. To avoid confusion, note that checking or unchecking the box next to a login item does not inactivate it. You have to delete the item from the list. – Linc Davis
Sure enough, there were about 3 items I removed. One was a folder called “Time” which could have been related to an old Time Machine Backup location I had set at the server at the time.