However, I closed and re-opened Outlook and it started syncing lots of data again.Īdditionally, I rolled out Outlook 2016 for Mac to 9x other computers. I left one of the Mac's syncing data last night and it appeared to finish as it said 'all folders up to date'. I wonder how can I fix this sync issue? Is there's something wrong with Outlook 2016 for Mac with large mailboxes? I also tried creating a new folder in webmail and that syncs ok. I checked the syncĮrrors tool but it reports no issues. In webmail, I moved itemsįrom another folder to the default 'sent items' folder, but that refuses to sync on the Mac Outlook (but the Windows Outlook synced ok). I cleared the folder cache but that made no difference, Outlook just says 'All folders up to date'. However, when I add the account to Outlook 2016 for Mac (Note: this is the first time Outlook has been used on this PC and it has the latest Outlook updates as of yesterday), only about half the folders and sub folders are showing. In Outlook 2016 for Windows I let it synchronise and all folders, sub folders show correctly once I choose 'keep all mail offline' In Webmail I can see all the mail items and folders. It has quite a few folders and sub folders. I have an O365 Exchange online P2 mail account with about 14GB of data in it that I migrated from IMAP recently.