uploaded files disappear from the profile after changing other profile data

New members of my website need to upload several files to complete the CB registration form. In the next step the administrator adds (in the backend) a specific reference number to the profile of each new member. A message is mailed that says that not only a reference number is added to the profile, but it says also that the all uploaded files are empty. It ‘s even more strange that the administrator has not the opportunity to upload the missing files again (the file upload fields are not visible at the backend) and the uploaded files are still available in the member directory “plug_cbfilefield” . This problem did not occur in the CB version of last December…. Could someone tell me how this problem could occur and how I can solve this problem?

Are you conditioning the file fields with CB Conditional? If so unpublish CB Conditional in CB > Plugin Management and see if your issue persists.

Yes, the problem did not occur when I unpublish the plugin CB_Conditional. I hope that this step is only required to find the rootcause of my problem. Or does this mean that this plugin is not supported in the current CB version?

That means you're conditioning away the field in profile edit. This will result in the fields value being emptied as it resets the value of the field. Either turn off value resetting within the conditions of that field or more than likely you need to fix your condition as it doesn't seam to be working correctly.