Forum Discussion
Outlook Desktop M365 error: "This is not a valid file name." when sending email with no attachments
Latest version of Office Desktop - for some new email, when we reply, we get an error message popping up: This is not a valid file name. There is no attachment on the email, we're just replying to t...
I have also been getting this error for about a month now. For some reason, it is only out of a specific inbox folder. The same user can forward or reply from the web app and from their phone but gives the error from the desktop app. (We have tried both office 2019 pro and M365). Reinstalling will work for about two weeks until the issue pops up again. gt-sea