This Error message comes when you are trying to upload image,music or video files which are not supported by wordpress.
WordPress have some whitelist of file types which are allowed to upload, Other files are not allowed to upload due to the security reasons.

Accepted Filetypes
Images
- .jpg
- .jpeg
- .png
- .gif
For More information Read WordPress Images
Videos
- .mp4
- .mov
- .wmv
- .avi
- .mpg
- .m4v
Audio
- .mp3
- .m4a
- .ogg
- .wav
Documents
- .pdf (Portable Document Format; Adobe Acrobat)
- .doc, .docx (Microsoft Word Document)
- .ppt, .pptx (Microsoft PowerPoint Presentation)
- .odt (OpenDocument Text Document)
For more information Read WordPress Supported fietypes


thanks for the video upload help!
How do we alter the allowable file types?
I’m trying to allow an .xml to the /uploads dir and it’s giving me the same “file type does not meet security guidelines, try another”
?
can we force it to accept a new file type?
You need to add the mime type to wp-includes/functions.php in WP 3.0 it is around line 2452 for xml can be expressed as application/xml text/xml see http://en.wikipedia.org/wiki/XML_and_MIME for more
Hope that helps
This is a helpfull comment. It should have it’s own post. Thax very much.
I’m trying to upload a standard word doc and it’s giving me this security guidelines message – in an MU blog. Any advice?
Thanks
Snilesh need your help.
1) How 2 change the font of Post/Page Title?
2) How 2 add an image(left,center or right) in Post/Page Title?
Hi Advance,
Nice thought.
Thanks a lots.
Sava Intl
Snilesh need your help.
1) How 2 change the font of Post/Page Title?
2) How 2 add an image(left,center or right) in Post/Page Title?
thanks for the upload video
Regarding: File type does not meet security guidelines. Try another.
I found out when replacing images in WordPress using Internet Explorer I get this error message. But when using Apple Safari or Mozilla Firefox I can replace images without any problems.
Hope this helps. But would like to know how to fix Internet Explorer.