This is important! Microsoft has positioned SharePoint, M365 Groups, and Teams as a set of tools that are easily used by ordinary citizen users and should not need the help or intervention of IT professionals. One important aspect of this goal is allowing non-IT end users to share content with other people. One aspect of this is to make it trivial to share content with external users. These users may or may not be part of the M365 ecosystem. As an IT professional with expertise in M365, I spend more time on helping external users gain access to content than any other issue or enhancement. This is not a sexy new feature, but it is bread-and-butter, and it is high time that Microsoft improve this experience.
There are many use cases for this type of collaboration. Just a few are listed:
- A company wants to share documents with investors
- A company hires various partners, and they need a secure store to collaborate on documents
- Scientists need to collect data from universities
- Financial firms need to gather information in a secure manner from customers
- Outsourced HR firms need to exchange data with clients
- Business Contracts need to be developed and disseminated
I have worked with dozens of clients and their M365 tenants. In most cases Microsoft gets a failing grade when it comes to making it easy for regular users to share content with external users (guests.)
Some people may argue that this is the nature of the beast. To those who are skeptical of my critique, I suggest that you try BOX, or Egnyte for sharing with Partners. I have asked Microsoft to fix these issues since 2015, but to no avail. (See But Does It Work?: Office 365 External Users: Microsoft, Please Improve! (typepad.com))
My friend and colleague Marc Anderson wrote: “When I criticize Microsoft it’s because I want to hold them to a higher standard than other tech companies.”
Depending upon how you configure your M365 environment, members may be able to share content. In the interest of simplicity, I exclusively focus on users who are Owners or have Full Control. This post catalogs a few key issues plaguing users who need to share with external users. Keep in mind that both the sharer and the recipient need to have very simple experiences. In all the cases cataloged below i have found that IT professional intervention is needed. In many of these cases I find that a screen sharing session helps resolve the problem quickly.
Issue 1: The Recipient User Experience When Accepting a SharePoint Invitation may be Confusing (The Devil’s Choice)
Imagine that you are a user being invited to a SharePoint environment.
Figure 1 illustrates how a user gets invited

Figure 1: Shows an external user is being invited from a SharePoint site
To drive the point home, I have run this scenario twice. I have two distinct environments (Tenant 1 & Tenant 2) that I use to invite a user in a third environment (Tenant 3.) The behavior is slightly different. This helps illustrate the frustrations that people can experience when inviting external users. (See Figure 2)

Figure 2: Summarizes our two experiences of inviting a user in tenant 3.
Figure 3 illustrates two invitations that are received. (They are separated by the red horizontal separating line.) I have sent an invitation to the same user in Tenant 3 from Tenant 1 & Tenant 2. One interesting thing to note is that we see two invitations that look slightly different.

Figure 3: These two screenshots (separated by the red line) illustrate that there are two distinct types of emails that a recipient may receive. We are not sure why the External User receives one or the other.
Most people (9 out of 10) will click on “IT” and if they are logged in to Tennant 3, they will get taken right into the SharePoint site as a guest. That is great! If they are not logged in, they will get the standard credential challenge for their M365 environment and once they provide credentials, they will be taken to the SharePoint site as a guest. The case we are interested in here is the anomaly which happens about 1 of 10 times.
When we click on “IT” we get taken to the page that I refer to as “The Devil’s Choice” (See Figure 4.) The recipient has no idea what this is asking. If they choose the wrong answer, this could doom them for a while, unless they get help from an IT professional. (We will elaborate on this in the section Issue 2.) By-the-way, you will notice that Microsoft has added the “friendly link”: Rename your personal Microsoft account. (What does that mean?)
The Devil’s choice is about disambiguating between a Live ID that you have (And you probably don’t know it) and your Organizational account. Similar to Figure 3, there are two distinct pages that the recipient may get taken to. Both pages are shown in Figure 4 and are separated by the red vertical line. Not sure why Microsoft is using different terminology in these two pages and why the order of choices is reversed)

Figure 4: Some people may get this dialog when accepting the invitation. I refer to this as “The Devil’s Choice.” Again, notice that I received the first page rendering from tenant 1 and the second page rendering from tenant 2.
Issue 2: A Citizen Owner (Full Control) Sends an Invitation to an External User, the External User is Rejected.
This problem seems to be tied to something in the inviting tenant. The issue depends on whether an external user is somehow known in the inviting tenant. We are using our three-tenant experiment to illustrate the issue.
In the first case a user in Tenant 1 invites a user in tenant 3 to the IT site. The user receives the invitation and clicks on the “Work or school account.” The user is taken to the page shown in Figure 5. This is one of the 1 out of 10 case. The recipient is flummoxed. At this point it usually takes some back and forth between the sharer and the recipient and finally I am called in.

Figure 5: Shows tenant 3's screen after click on the invitation from tenant 1: Note the browser was logged in as the user on tenant 3.
The solution to this is the “Ctrl-Alt-Delete” version of user profiles is the easiest way to deal with this problem. In tenant 1 we go into the active users find the offending external user and delete the user account. Then we wait 24 hours (probably didn’t need to wait this long) and reinvite the user.
This time when the recipient account holder clicks on the link in the invitation email and chooses Organizational Account, everything works perfectly.
Issue 3: A Citizen Owner (Full Control) Sends an Invitation the Email is Caught in the Spam Folder
This is a very simple concept. Microsoft makes sure that the emails that come out of LinkedIn do not get caught by peoples’ spam filter. However, SharePoint & Teams invitations often get caught by peoples’ spam filters. Certainly, Microsoft can do something to avoid this.
Issue 4: When a Teams Invitation Is Sent Out, the Sharer Does not Receive a Copy of the Invitation
When owners send out an invitation to a SharePoint Group, the sender will be copied on the invitation. This is great, because the sender can forward the invitation to the invitee if need be. In the case of Teams invitations, the sender is not copied. Therefore the sender is never quite sure that an invitation actually went out and they cannot forward an invitation.
Issue 5: If the Guest is Logged in to the Wrong Tenant, the user Cannot Access the Content
Of course, it makes sense that if a user is logged into the wrong system that they shouldn’t have access to content. The trouble is that the User Experience is quite confusing and especially as it pertains to the Microsoft Office Applications. Furthermore, it is not always clear-cut how-to login to the correct environment. Microsoft needs to simplify the process.
Issue 6: Distinct ways of Providing Access to SharePoint Content vs Teams Content.
If owners want to provide external users with read-only access, they must use the SharePoint group “Visitors.” It means teaching owners two ways of sharing. Many owners are confused by this. Furthermore, owners often want the guests to be able to see the other Teams content, but not be able to modify or contribute. Microsoft needs to find a way to simplify the permissions so that there is one reliable way of doing everything ab owner needs to accomplish.
Conclusion
Microsoft SharePoint and M365 Groups (Teams & Groups) provide a great deal of sharing functionality. Issues abound that require the intervention of IT experts to help in many cases of sharing with external users. Other Collaboration services (Egnyte & BOX) are much easier to use. Microsoft should fix these issues.