Notes about the IDENTIFIER file extension:
To open this file type, a required software must be installed. Without it you only see a Windows message "The following file cannot be opened
" (Windows 7) or "How do you want to open this file?
" (Windows 10) if you double-click the file. There click on "More apps"
and choose a suitable software to view such files on your PC or from email attachments.
The IDENTIFIER file type is primarily associated with 'Internet Explorer' by Microsoft Corporation. You won't normally see this file extension and if you do it should be attached to a filename with a colon and "zone" before it (e.g., FILENAME.DPC:ZONE.IDENTIFIER). This type of file name might be revealed by a rootkit identification program. When you use Internet Explorer to download a file that can have executable content (.DOC files, for example, can have executable macros in them) IE adds an NTFS Alternate Data Stream named ZONE.IDENTIFIER to the file. The ADS subsystem allows additional data to be linked to a file. The additional data, however, is not always apparent to the user. If you open a Command Prompt window, navigate to the folder containing the file, and command
MORE < FILENAME.DOC:ZONE.IDENTIFIER
(substitute the name of the file for FILENAME.DOC in the command) then you should see the contents of the ADS attachment which should be a couple of lines identifying the assigned Internet Zone when the file was downloaded and saved. If you trust this file you can right click it, select properties, and on the general tab click the unblock button.
Detailed information for file extension IDENTIFIER:
Primary association: Internet Explorer
File classification: Text
To change file associations press Windows Key
and then Apps and Features
> Default apps
> Choose default apps by file type
Invalid file associations could be the result of underlying issues within your Windows PC.