We are using HPE RM V18.104.22.16888 and Outlook 2016.
We have configured the "Update style for an email message that has been processed" option in Dropped Files to be "Update the email message with an 'In HPE Records Manager' indicator. This is pushed out through global settings, and I verified the setting on my desktop client. Dragging and dropping an email message into HPRM does not update the record in Outlook. Putting the message into a linked folder and having it processed, on the other hand, does update the record in Outlook, by prefacing the subject with "HPRM:".
While performing a specific test of the above issue, I received a warning message stating "The email has successfully been registered into HPE Records Manager. However the attempt to remove or update the subject of the email in Outlook failed. It was not possible to find the eail as the permanent email id could not be discovered within the EML email file. This is due to the System Option to save email in EML format. Try using MSG format instead." This message seems to be somewhat randomly received. What is the "Permanent email id"? In HPRM, the messages that I registered have a Message ID and a Conversation ID in their properties, so it isn't that, I guess.
With regard to the recommendation that I use MSG format instead of EML format, I've not seen such a recommendation before. None of the documentation or help says anything about the EML format having shortcomings. I like it better. I had decided to stay with the EML format since a large number of our existing records had already been converted from VMBX to EML. Now I wonder if that was the right choice.