I am currently having issues with the Harmon.ie Outlook add on. The sync option has become grayed out and disabled suddenly. example
The sync option had been previously working correctly.
Is there any steps to trouble shoot this issue?
-Are you running Office 365 online site? If not, check whether the button is still grayed on top of Office 365 online location.
You are probably running new OneDrive client (MS process used to perform the sync).
The article at: https://support.office.com/en-us/article/Which-version-of-OneDrive-am-I-using-19246eae-8a51-490a-8d97-a645c151f2ba details about the two clients and which one requires Office 365
Article at: https://support.office.com/en-us/article/Get-started-with-the-new-OneDrive-sync-client-in-Windows-615391c4-2bd3-4aae-a42a-858262e42a49 says: “the new OneDrive sync client supports Windows 10, Windows 8.1, Windows 8, and Windows 7. The OneDrive sync client doesn't yet support on-premises instances of OneDrive for Business (when your organization doesn't subscribe to an Office 365 business plan).”
Article detailing transition between old and new client: https://support.office.com/en-us/article/Transition-from-the-previous-OneDrive-for-Business-sync-client-4100df3a-0c96-464f-b0a8-c20de34da6fa
----- Jean