Solution for Outlook error: This is not a valid file name

Outlook client giving error when replying or forwarding email chain, with or without attachment and getting an error: “This is not a valid file name”. The issue could be local outlook setting, plugin as well links, or images broken. The best way to check via Web outlook is to test your issue, if the web works then look at the settings of outlook. Here are some options that may help fix your issues.

Error messages:

This is not a valid file name
Cannot send this item

Look at the body of the email:

Look at all links and empty areas of the body to see if there are any hidden links, Like the example below

Once removed any broken links, your issue should be fixed

Also, you can try converting the HTML to Plain Text, which will remove all formatting and links

Convert HTML to Plain Text or Rich Text

Check outlook in Safe mode:

Click Start > Run.

Type Outlook /safe, and choose OK

Take a look at the Plugin of outlook:

You can get to it by going to File>Options>Add-ins

Just uncheck to disable whichever you don’t use or causing the issue

Add-ins

That’s it, hope it helps some people



How to change the view on Outlook

There is a number of ways to change the view and options you can choose from. Most common is having to be able to view these headers so you can sort them, they are From, Subject, Received, Size and Attachments

Based on the size of the screen you might only see this, which means you can need to change size or decrease the Characters from default 125 to like 75 or whichever works for you.

Screenshots are from Outlook 365, but other versions have similar settings too

You can change by going into View>View Settings>Other Settings…>under Other Options

If you like you can add other columns which you like too, it’s all customizable, if you changed something and you don’t like you can Reset the view to default by going to View>Reset View

That’s it, hope this helped out