Recently had a user who was sending emails with the following displayed in Outlook

I thought this issue and error was displaying when a user emailed back his email , however later I found out this was actually the error that showed when he created a new message using the signature

The issue was the email signature was referencing a server share and the PC was not on the domain

To fix this if you manually copy the images to the local machine you can edit the .htm file in the signature folder then find the HTML which references the incorrect image location and reference the new location where you saved the images to