Dear Atlassian Support,
I backuped the Jira XML file + Attachment folder.
Then i Import the Files in a Fresh Jira installation for some reason the folder wich the Attachment are in doesnt create new folders.
Wich resaults that when a customer reply to a E-mail it wont show it as a comment on the Jira site.
Disabling the Attachment function lets resaults the function to work again.
I am not sure I fully understand the connection between attachments being enabled/disabled and the abiity for a user to reply to an email and have Jira create a comment from that.
Perhaps if the user's email client is always including an attachments such as an image or a footer of some kind, Jira would try to store that attachment to the Jira issue itself.
My thought is that this new Jira installation might not have the needed filesystem permissions necessary to be able to store that attachment. This would make sense since if you disable attachments, Jira then doesn't have to try to store this file. But if this was the case, then you should be able to see errors in the $Jira_home/log/atlassian-jira.log file that indicate as such, with an error message like "unable to create directory, access is denied"
Are you running JIRA in a Windows environment or a Linux/Unix environment? If in a Linux/Unix environment there is a KB that explains what permissions you should have set so that the user account running jira can actually create new folders to store attachments locally. Please see How to fix Jira directory permissions in Linux.
If you're using Windows, the concept is the same, but the comamnds would be different. If in windows, I would recommend navigating to those two respective folders:
If you right click on these folders and go to Properties -> Security, you can also check out the file system permissions and make sure the user account (or service account if starting JIRA as a service) has the proper permissions to be able to read/write/create directories under each of these main folders and their subfolders.