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 fix outlook error opening attachments

Cannot create file

Getting errors when trying to open an attachment from Outlook something like “cannot save the attachment.¬† Cannot create file: FileName.pdf. Right-click the folder you want to create the file in, and then click Properties on the shortcut menu to check your permissions for the folder.” This may be due to permission or a corrupted temp directory. Here is how to fix it, one thing you could try without doing anything is to restart the computer, if that does not fix try the following options.

Error message:

Option 1: rename temp folder

The temp folder of outlook is located at the following location: “YourUserName” which would be your own user name, anything after Content.Outlook\ would be randomly created folder name by an Outlook

Make sure your Outlook is closed, then rename to old or anything you want or simply delete it. Then re-open the outlook, it should recreate the temp folder and your attachment should be fixed

C:\Users\YourUserName\AppData\Local\Microsoft\Windows\INetCache\Content.Outlook\T9U9A03U\

Option 2: Regedit

Please be very careful of changes in the registry, your computer could be non-functional if you make wrong changes, so do it at your own risk. Make sure the outlook is closed

First, open the registry by going to RUN>type regedit

then search for “OutlookSecureTempFolder”

Based on your version of outlook location will be slightly different

  • Office 365 Outlook:
  • Computer\HKEY_USERS\S-1-5-21-1014573083-3332314220-1222384373-8206\SOFTWARE\Microsoft\Office\16.0\Outlook\Security
  • Outlook 2013:
  • Computer\HKEY_USERS\S-1-5-21-1014573083-3332314220-1222384373-8311\SOFTWARE\Microsoft\Office\15.0\Outlook\Security
  • Outlook 2010:
  • Computer\HKEY_USERS\S-1-5-21-1014573083-3332314220-1222384373-8311\SOFTWARE\Microsoft\Office\14.0\Outlook\Security

Then change the OutlookSecureTempFolder location to somewhere you have access. Remember this is the default location, if you do change the custom, and when an update applies it may revert. When you open the outlook it should work now, you should see new random folder after your default location.

That’s it, hope this helps others out there