Over the last several days I have noticed issues with sending, and sometimes receiving, emails from Outlook 2016. Often, Outlook 2016 would report that it was disconnected — the Microsoft Exchange message at the bottom of Outlook that indicates connected or disconnected or Working Offline. This morning, things got worse. I had sent a couple of messages that went through, but in my Sent email folder it showed that the messages were copied to a couple of other people and attached a image001.png file I did not attach. I had no idea why that happened, so I started to search help and online.
There were some references online to attached image001.xxx files, mostly regarding the use of signatures, html, or stationery in emails. I did not use a signature or stationery, so I focused on html and turned on plain text. This made no difference for me, so then I just focused on the disconnection issue.
I finally came upon a solution that worked, mentioned in the Microsoft Community on Microsoft.com. Back in August 2016, this user had a similar issue to mine where Outlook 2016 was often disconnecting them. The solution that worked for them — “removing and then adding the email account back into Outlook…” — also worked for me. At least so far! Also, when I looked at the messages that previously seemed to have an attached image001.png file and a couple of people I did not send to, the messages were now correct (no wrongly attached files and no people copied).
Just because this worked for me, I cannot guarantee it will work for you. I am only posting this in case it helps someone who has the same issue as me.
Removing my Exchange email account and adding it back in from Outlook 2016 was easy. I went to File-Account Settings in Outlook 2016, then selected the email account I wanted to remove. Then I clicked on Remove (make sure you have the right email account selected, if you have more than 1). Then I clicked on New, to add my email account back in (you’ll need your password and email address). This is for an Exchange email account, so I have no idea what to do if you have disconnect issues with a Pop3 or other-than-Exchange email account.
Note that removing your email account from Outlook also deletes your associated email .ost file (offline folder file for synchronizing with the Exchange server) and recreates it. If you have a lot of email on the server, it will take some time for Outlook to recreate this .ost file. I have most email in local folders, so it only took a few minutes and my .ost file was completely restored.