How to fix Error illegal or invalid mime type detected in Joomla 3.7

This error has been reported in some installations of Joomla 3.7 and it happens when you try to upload a pdf or text file through the media file browser you get the message Error illegal or invalid mime type detected.

This can be quite frustrating especially if you need to urgently get some documents or the other uploaded to your website.

Luckily, there is a quick and short fix to this:

  1. Login to your Joomla Backend.
  2. Go to The System Menu and select Global Configuration.
  3. Under the component menus, select Media.
  4. In the Media Section, scroll to Ignored Extensions
  5. Type in the following text highlighted in red   application/pdf,pdf,txt,text/plain

Save your settings and you will be able to upload your pdf and text files again easily