I have a 4 computer business network, all computers running windows 7 professional 32 bit. Spent a weekend getting Mail Merge Extension to work. Was in middle of a mailing. Bumped against the Gmail daily sending limit. Tried again and got message: "Sending of the message failed. No recipients were specified. Please enter a recipient or newsgroup in the addressing area." Clicking OK gets: "[Exception... "Component returned failure code: 0x805530df [nsIMsgCompose.SendMsg]" nsresult: "0x805530df (<unknown>)" location: "JS frame :: chrome://mailmerge/content/compose.js :: mailmerge.send :: line 821" data: no]" Clearly the Mail Merge wasn't pulling the data from the .CSV. Took th e data file home and Mail Merge worked. Went back to work (next day) and got above results. Installed Thunderbird and Mail Merge on a different (networked) computer using the SAME data file across the network, everything works fine. Went back to original computer, merge failed per above. Created a little test .CSV file with 3 fields and 2 records, merge failed. Uninstalled Mail Merge, Uninstalled Thunderbird and shut down the computer (complete power off), restarted it, reinstalled Thunderbird, reinstalled Mail Merg Thune. Getting same errors with same data files! Put Thunderbird and Mail Merge on a second computer on our business network. Everything worked find. Hit the GMail Daily Sending limit and the same thing happened. Got Thunderbird and Mail merge working on a 3rd computer. Everything works ok. Tried to fix computer #1. Uninstalled mail merge, uninstall Thunderbird. Rebooted the computer, reinstalled Thunderbird and mail merge. Same problem. GMail says it is not their problem. Ran the System File Cheecker... no problem found. Mail Merge still fails. Tried to fix computer #2 by installing windows on top of windows. Mail merge still fails on that computer. Even though mail merge fails, Thunderbird works correctly sending and receiving EMails... just ''[Formatting fixed by moderator.]''