Outlook 2016 has stopped syncing certain Gmail labels Outlook 2016 has stopped syncing certain Gmail labels. Hi, Some, but not all, Outlook 2016 folders have stopped syncing with G-mail through IMAP. The issue seems to be completely random . . . for example, "All Mail" stopped about a month ago. So, initially thought it may have been a folder size issue, as my ost file is 32GB.