File zipping download issue

I am using Mendix modeller 7.17.2 and CreateZip version of 1.0.6. File zipping is working fine for me in a sample app. But when I put it in to project, it is not working. Its showing the size of zipped file as almost double of files to be zipped in message box. But zipped file is not downloading. Can anyone help me on this? When I call download activity inside loop, files are downloading.           
1 answers

You should never use/expose an object of the base entity type System.FileDocument.

Use a specialization with proper security settings for users to read it.