Sending of email with certain files (perhaps only PDFs) fails with the following message: "There was a problem including the file Monroe Co Ridgeville II Feasibility Determination Project Summary 05-31-19.pdf in the message. Would you like to continue sending the message without this file?" See screen shot attached. This only affects emails with attachments and not all attachments. The email will still go through without the attachment. This is with Thunderbird v60.7 running on Linux Mint 19.1. Recently updated Thunderbird. This has affected 2 of the 5 computers in our office running the same OS and version of Thunderbird. Thanks!