Zone.Identifier is a stream generated by Windows Internet Explorer and Outlook for storage of URL security zones.
How to disable :Zone.Identifier stream
You can disable it by applying following setting through gpmc.msc
1).Run the gpmc.msc
2).Click the Default Domain Policy and click Edit
3).Go to the Setting: User Configuration ->Administrative Templates ->Windows Components ->Attachment Manager
4) Now, you can enable the setting Do not preserver zone information in file attachments
Note: refer below screenshot