What is the code you are using? Did it ever work or is it a new error? Was anything changed?

That's a weird one. For weird stuff I usually say to check the Troubleshooter.

Usually stuff like that involves uninstalling (completely) and reinstalling Office.

@Adam i have a global variable - i will post below - that works fine on my PC, but fails on others. So all my testing i never came across this issue until we started small scale testing. This is getting pushed out to the whole company by the end of the month, so really need to get this sorted 😥. The MD is one of the PC's having issues.

@Rich i really dont want to go down that route if i can help it!!

Public Sub SendEmailTO(EmailTo As String, msg As String, Email As String, EmailCC As String, EmailSub As String, Q As String, PO As String)

    Dim objOutlook As New Outlook.Application
    Dim objEmail1 As Outlook.MailItem
    Dim Signature As String

    Set objEmail1 = objOutlook.CreateItem(0)           'olMailItem)  <--- I thought this was the issue, but removing it only helped some users not all

    With objEmail1
        .Display    
    End With

    Signature = objEmail1.HTMLBody

    On Error Resume Next
    With objEmail1
        .To = EmailTo
        .CC = EmailCC
        .subject = EmailSub
        .BodyFormat = olFormatHTML
        .HTMLBody = msg & _
            Signature
        .Attachments.Add PO
        .Attachments.Add Q
'        .Display
        .Send
    End With
    On Error GoTo 0
    
    Set objEmail1 = Nothing
    Set objOutlook = Nothing
End Sub

I wouldn't do both a .display and a .send. Pick one or the other. Either show it to the user so they can make changes and hit send themselves OR send it immediately.

the display is comment blocked. I use it for testing. So in the above code it is just sending.

Hi Tyrone, if you don't want to reinstall Office, you can try to repair it.  Click the Start button, go to System, Apps, choose Outlook (or Microsoft 365, Microsoft Office), choose to "Modify" it, and you will get the option to repair it.

Hi

I thought i would update you with how i have managed to get it working... for now anyway.

I changed my code in the top so that it checks to see if outlook is open first, if it is open it opens a new email, if it is closed it opens an Outlook instance and then a new email. This seems to be working for now, but will update it i find anything else. See code change below.

Dim objOutlook As Object
    Dim objEmail1 As Object
    Dim Signature As String
    
On Error Resume Next
    Set objOutlook = GetObject(, "Outlook.Application")
    If objOutlook Is Nothing Then
        Set objOutlook = Nothing
        Set objOutlook = New Outlook.Application
    End If
On Error GoTo 0

Thanks for sharing