Forum Discussion
Outlook Desktop M365 error: "This is not a valid file name." when sending email with no attachments
gt-seaI also get this and it has only started happening in the last month or less I think. Only happens in desktop version of Outlook
If I reply or forward some emails I get the same "This is not a valid file name" error message.
Fix is to look for and delete any images that are in the body of the email then it will send ok. I think it has to do with broken image links but not sure.
- gt-seaDec 13, 2021Copper ContributorThanks k-mccoy for the suggestion, we have found that if we have a long email thread we can chop away at the bottom of the thread and get it to go, but that is not really an acceptable workaround for most users. And for some emails, it is the 1st reply to the email so what could not be correct about an image? The email was just received 2 seconds ago and it looks fine.
If there is something wrong with an image in an email then Microsoft should highlight that image at a minimum so the user can delete it and move on OR is should just allow us to send the email. Nothing is a bigger waste of time than to write-up your reply, hit send and then get told "... not a valid file name" and you can't send the reply.
Frustrating here - this has been going on for over a month and Microsoft knows about it and can't tell us why this is happening.- ITGDarylDec 14, 2021Copper Contributor
gt-sea Ah, someone else experiencing the same issue, I really struggled to find any info on this around the web before now.
I have done some digging myself, it seems also that if you click away from the email (quick reply/forward) so it remains a draft email in the list of emails for whatever folder you're in and then switch back, the entire email body vanishes and becomes totally blank.
It acts as if wherever it caches this while writing the reply is beyond the windows character limit, however, I have tried outlook in online mode with no caching enabled, I have cleared appdata, cleared temp files, checked while writing emails for anything generated in temporary internet files or other locations and not found anything.
Hope we can find a solution to this, but also somewhat glad to see it's not just me going crazy!
- gt-seaDec 14, 2021Copper Contributor
Thanks ITGDaryl. Sorry you are having similar problems but kinda glad others are reporting this issue - maybe Microsoft will put some resources behind trying to solve this. I have an open support ticket with Microsoft about this issue and the ticket was opened on 11/9 and Microsoft really has done nothing to resolve the issue. I'm on my 4th ambassador (the last one went on holiday and I found out 2 days later when ambassador #4 introduced himself).
I would think they could have an Outlook Desktop SME look at this issue and see what is triggering the error in the desktop software. Email message is fine in OWA and/or on Phone APPS - so what in the email does Outlook Desktop not like?