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Fix "assignedTo contained no valid users" in a Power Automate approval

No one in the approval's Assigned to box matched a user in your tenant. Find the value the run sent, then fix the usual causes: names, separators and guests.

Power AutomateFix a problem7 min read

Checked against Microsoft Learn · 8 sourcesPosted by the Maker DeskHow we write guides

Your approval flow fails on Start and wait for an approval (or Create an approval) with InvalidApprovalCreateRequestAssignedToNoValidUsers and the message "Required field 'assignedTo' contained no valid users in the organization." The approval was never created, so nobody was asked. Power Automate looked up every entry in the Assigned to box in Microsoft Graph, your tenant's directory, and couldn't match a single one. The fix is nearly always in the value the flow passed in, not in the approval action itself.

What happens to the value in an approval's Assigned to box. The value is split at each semicolon, and each entry goes through two checks. Check 1: is it a well-formatted email address, user principal name or Microsoft Entra object ID? A display name such as Avery from Finance, or two addresses separated by a comma, fails here. Check 2: does it match a user in Microsoft Graph? An address for someone who has left, or for an outside person who was never invited as a guest, fails here. Guests who haven't accepted their invitation are removed from the list. If no entry passes both checks, the run fails with Required field 'assignedTo' contained no valid users in the organization. The fixes: use the person column's email or the user's UPN, separate several people with semicolons, replace people who have left, and have guests accept their invitation first.
Every entry must be a real user Graph can find; if none is, the approval isn't created.
View full size: Every entry must be a real user Graph can find; if none is, the approval isn't created. (opens the image)
  • The approval action fails with Required field 'assignedTo' contained no valid users in the organization and the code InvalidApprovalCreateRequestAssignedToNoValidUsers.
  • Assigned to is filled from dynamic content or an expression, not typed in.
  • It fails for some runs and not others, depending on who the item belongs to.

What the error means

Microsoft documents three reasons for this error:

  • an entry isn't a well-formatted email address, user principal name (UPN) or Microsoft Entra object ID;
  • an entry is well formatted but doesn't match any user in Microsoft Graph;
  • with several people separated by semicolons, none of them was found.

The last point matters: Microsoft describes the error only for the case where no entry is found. So a list where one address of three is wrong doesn't raise it, and the mistake can go unnoticed. When you do see the message, every entry failed.

See what the run sent

The value in the designer is often dynamic content, so check what it turned into for the failed run:

  1. Open the flow's run history and select the failed run.
  2. Select the approval action to see its inputs, and find the assigned-to value.
  3. Compare it with what Graph expects: something like approver@lowcodestacks.com, one per entry, separated by ;.

If the input is blank, you have the related "missing or empty" error instead (see below).

Common causes and fixes

What the run sentWhy Graph can't match itFix
A display name, such as Avery from FinanceIt isn't an email, UPN or object IDUse the person field's Email, or look the person up with Get user profile (V2) from Office 365 Users and pass their email or UPN
Two addresses joined with a comma, or a space-separated listThe whole string is read as one malformed entrySeparate people with semicolons: a@lowcodestacks.com;b@lowcodestacks.com
An address with extra text around it, such as spaces or a name in angle bracketsNot well formattedClean it with trim(), or build the list with Select and join(…, ';')
The address of someone who has leftTheir account is gone from Microsoft Entra IDReplace them, for example with their manager from Get manager (V2), or a fallback approver
An outside person's own emailThey aren't a user in your tenantInvite them as a guest in Microsoft Entra ID first
A guest who hasn't accepted the invitationPending guests are removed from the approver listHave them accept; if every approver is a pending guest, the approval can't be created
A group's emailOnly mail-enabled Microsoft 365 groups and security groups are supportedUse one of those, or list the people

What the approval card shows in the designer, as Microsoft's screenshots show it in 2026:

  1. Approval type, such as Approve/Reject - First to respond.
  2. Assigned to, required, where you type a name or email to pick people, or add dynamic content.
  3. Switch to Advanced Mode, beside it, where you can enter the value as an expression.

Tip

Guard the action. Before the approval, add a Condition that checks the assigned-to value isn't empty and contains @, and send anything that fails to a fallback approver or an owner's inbox. The flow then never stops silently on a bad row.

Guests

Microsoft supports approvals for guest users, with conditions: they must have accepted the B2B invitation, and they need a Power Automate licence (from your tenant or their own) to view and respond. A guest's approval can't be answered from an actionable email in Outlook; they respond in Power Automate. To check a guest's status, in the Microsoft Entra admin center open Users > All users, select the guest, and check the invitation status on their profile.

The related approval errors

Microsoft lists these alongside it. They look alike but mean different things:

CodeMessageWhat to fix
InvalidApprovalCreateRequestAssignedToMissingRequired field 'assignedTo' is missing or empty.The dynamic content or expression was empty for this run, often a blank person column
InvalidApprovalRequestorThe approval requestor must be a single, valid user account within your organizationThe Requestor field: one user only, as email, UPN or object ID
GraphUserDetailByEmailMultipleFoundFound multiple matching users (…) for '…'.Two accounts share the address; an admin needs to sort out the duplicate
XrmApplyUserNotMemberOfSecurityGroupCould not create a CDS system record representing user '…'. …The environment is locked to a security group the person isn't in; see our guide to environment security groups

Do

  • Pass emails or UPNs, never display names, and join several people with semicolons.
  • Keep a fallback approver for rows whose person has left or is blank.
  • Invite outside approvers as guests, and check they've accepted, before the flow needs them.

Don't

  • Don't assume a partly wrong list will fail: this error only appears when nobody in it was found, so check every entry.
  • Don't put several people in Requestor; it takes one.

Once the approval is created, our guide to approvals that don't stall adds deadlines, reminders and escalation, and approval actions compared helps you pick the right action and type.

Sources

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