Office 365 - Known Issues

Last Updated: 12/06/2019

General Issues

Conflicting Accounts

  • Issue: If you have created a Microsoft account using your account, you will technically have two separate accounts with the same username. Other than the username these accounts are completely independent of each other. To understand the difference refer to The Difference Between a Microsoft Account an Office 365 Account article.
  • Workaround: There is currently no workaround known, other than deleting the Microsoft account and creating a new account with a separate email address.

Outlook 2016 for macOS and iOS login loop

  • Issue: Some users with Outlook 2016 for Mac have gotten into a login loop and cannot access their mailbox, despite entering the correct password. 
  • Workaround for macOS:
    • Close Outlook
    • Open Microsoft Excel and log on to Office 365. (You may need to log off Excel first, then log in again to force reset)
    • Once Excel is logged on properly to Office 365, re-launch Outlook.
  • Workaround for iOS:
    • Update iOS to the latest (currently 10.2.1.) if the hardware is new enough to support it. (Older hardware, such as the first gen iPad or first gen iPad Mini will not update sufficiently).
    • Update Outlook for iOS to the latest version in the App Store.
    • If Outlook is prompting for signing on, go into Settings > Select the account > Reset Account.
    • If that fails, Delete the Account and re-add it.

Microsoft OneDrive for Business Known Issues

OneDrive Applications cannot view Shared Files

  • Issue: Currently, the desktop and mobile applications for OneDrive are limited to viewing files owned by your account.
  • Workaround: Use the web version of OneDrive to collaborate on files and documents shared with you.

Exchange Online Known Issues

Accessing Office 365 Email with Safari

  • Issue: Users attempting to access their Outlook Web Access email in Safari versions 13.0.3 on macOS Mojave 10.14.6 receive the error, "We couldn't sign you in. Please try again." and are unable to log in at all. This happens if the links,, and are used or if they attempt to access their email after logging in through a different link. This issue is happening for other organizations with Office 365 and is not limited to CU Boulder.
  • Resolution: Microsoft is aware of the issue but has not provided a resolution yet.
  • Workaround: Access OWA in Chrome or Firefox until the issue is resolved.

Outlook Web App Add Room List Limitation 

  • Issue: Outlook Web App can only display up to 100 rooms in the "Add Room" tool. So when you try to reserve a room for a meeting, unless your room is one of the first 100 alphabetically, it won't be displayed in the list. 
  • Workaround: You must add the room you wish to reserve as an attendee of the meeting.  
    • From the Calendar app, click "New" in the upper-left corner of the screen. 
    • Type the name of the room you would like to reserve in the attendees field. Most rooms follow a department abbreviation, building abbreviation, room number naming convention (e.g., ENG-HLMS-124). Select the room. 
    • Make sure to also enter the room name in the "Meeting Location" field so it's displayed to attendees. 
  • Last Updated: June 18, 2015

Large Mailboxes Cause Email Program Slowness 

  • Issue: Mailboxes in excess of 10 GB may cause email program performance issues such as slow loading.  
  • Workaround: If your mailbox exceeds 10 GB, you can reduce the size of your mailbox by archiving or deleting messages, or by disabling caching. Please note that disabling caching can also cause performance problems. Microsoft Outlook 2013 provides better caching options--for instance caching only 12 months of email--than other Windows email programs. Please refer to our Tips & Tricks page to learn more about caching with Exchange Online. 
  • Last Updated: June 18, 2015

Calendar Invitations Appear with "not supported calendar message.ics" Attachment 

  • Issue: Sometimes calendar invitations do not display and instead have a "not supported calendar message.ics" attachment. This can happen when an invite is sent from an email program that has calendar logic that Outlook doesn't understand such as Lotus Notes or when an invite is sent from a secondary account. 
  • Workaround: Opening the attachment should display the invite specifics and allow the attendee to accept or decline the invitation.  
  • Last Updated: June 18, 2015

Apple Mail Sends A Copy of Reply-All Emails to Me

iOS Mail Drafts Don't Sync with Exchange Drafts Folder 

  • Issue: The iOS "Drafts" folder in Mail does not sync with the "Drafts" Folder on Microsoft Exchange Server. So when creating a draft on an iOS device, it will save locally on the device, but not in Exchange Online. This is a known issue.  
  • Workaround: There is no workaround at this time.  
  • Last Updated: June 18, 2015