Markzware is a legendary name in the desktop publishing industry, famous for its file conversion and preflighting tools. While they primarily sell standalone software, they also offer cloud-based and streamlined conversion options through their IDMarkz technology.

I can provide specific troubleshooting steps or recommend batch conversion tools based on your needs. Share public link

Drag and drop your .indd file into the upload box. Keep an eye on file size limits, as massive catalog files with embedded graphics may exceed free tier limits.

Confirm the converter site uses SSL encryption (look for the padlock in the URL bar).

Ensure the target format dropdown is set specifically to .idml .

If you want to ensure your files translate perfectly during this process, I can give you more specific advice. Let me know: What your recipient or printer is using The total file size of your current INDD project

Fortunately, the InDesign Markup Language (.idml) format solves this problem. This comprehensive guide explains how to use an online converter to transform INDD to IDML, ensuring your files remain accessible across different software versions. Why Convert INDD to IDML?

If you are converting because you need to share a file with someone using an older version, would you like to know how to a file to ensure they have all the images and fonts too?