Thanks, Ken. This fixed the issue.

The exception is thrown on the first file. The files have different GUIDs, as you can see in the screenshot.

I have included a screenshot of the debugger. Let me know if you need any other information.    

How can I specify which MIME types to check? That was my initial question. How do I set the ValidateOption.AllowedFileMimeTypes property? Would you please give me an example?   Also, this link that you provided (http://www.ajaxuploader.com/document/index.htm#page=html/How-to-catch-uploader-error.htm) does not give specific instructions on ...

Hi Ken,   I want to check the MIME type because the user can easily bypass the file extension validation by renaming the file. Does this control support MIME type checking?

Hi Ken,   I tried a different folder and got the same exception. Here is the ASPX code:  <CuteWebUI:UploadAttachments runat="server" ID="MultiFileUploader"                 InsertText="Add a ...

Hello,   When I try to save an uploaded file using the MoveTo method, I get the following IOException:   "Cannot create a file when that file already exists."   The folder I am trying to save the file to is empty! I tried passing both absolute and relative paths to the method, but to no avail. What is the ...

Hi,   There is no documentation for ValidateOption.AllowedFileMimeTypes. How can I use this property to limit the file types a user can upload? And more importantly, where can I set the error message shown to the user if he/she uploads a file with an invalid type?   Thanks.