Exchange 2016, Outlook 2016+, O365
I have been using a custom Outlook 'Organisational' form for last 15years that adds a UserProperty 'ProjFile' to an outgoing email via VBS, and BCC's it to a mail-enabled public folder (ProjFiling).
An separate app then polls the public folder for items, reads the 'ProjFile' property and moves that email to a relevant public folder.
set objRecip= ThisEmail.Recipients.Add("ProjFiling@ourdomain.com.au") objRecip.Type=3
objRecip.Resolve ThisEmail.UserProperties("ProjFile") = sProjId & "-" & sFileAs
All user mailboxes have recently been transitioned to Exchange Online, with the PF mailboxes (320Gb) still on-premises so we can use Sharepoint & Teams more effectively.
BUT. the userproperty is not being saved on the copy of the email within the ProjFiling PF, but it does remain when email is received by an internal Outlook user. (it displays on the Organisational Form);
so outgoing emails are not able to be filed without user action.
I suspect the problem is caused by ExchangeOnline removing all the properties when sending the the PF mailbox onprem.
Looking for ideas or settings to reinstate situation.