Platform: All Platforms Versions: All versions

Problem Description

Email servers may reject larger file attachments. If you want to provide COMSOL staff with model files larger than 10 MB, you can create an FTP directory to upload them.

First, see if you can reduce the size of the file that you are trying to send by removing solution data and compacting the file, as described here: Knowledge Base 1238: Reducing the size of your COMSOL Multiphysics file Sometimes, though, you may want to send a file with a solution, in which case you may be able to reduce the amount of solution data as described here: Knowledge Base 1255: Reducing the amount of solution data stored in a model

After following the above steps, your model may already be below 10 MB in size.


The following video shows you how to upload a large file to a COMSOL support case using an FTP directory. Please note that while we use the Internet Explorer® browser, the steps are applicable to other web browsers as well. Additionally, step-by-step instructions are listed below.

  • Make sure you allow pop-ups in your browser.
  • Create a new support case (Click here) or click Reply in an existing support case.
  • Click the Create FTP Directory button. This opens up a new window or tab in your browser, depending on your settings.
  • Upload the files to the created directory (see supported procedures below). Please note that you might not see the uploaded file as you don't have read permissions. To see the file, proceed with the next step.
  • Click the Refresh File List button to see the uploaded files in your support request/reply. This is needed if you want to remove a file that you do not want to attach to your message.

Below are the supported methods to upload your file to the created FTP directory. If prompted for user name and password, enter the user name anonymous and leave the password blank.

  • In Windows: Start a Windows Explorer (file browser) and copy the url from the new window/tab in your web browser to the address field of the Windows Explorer. Copy the files to the folder. Watch the video above to see these steps demonstrated.
  • In Internet Explorer, press Alt and select View > Open FTP site in Windows Explorer. Then drag and drop files or directories to the opened folder. Note: In Windows 10, copy the url manually, as suggested in the first bullet.
  • In Firefox, you can try the FireFTP add-on.
  • Use the dedicated ftp client FileZilla.
  • On Linux, Mac or Windows you can use the ftp command at a command prompt.
  • Currently, Chrome has no supported add-on.