.ZM3 File

The zm3 file extension is associated with ZoneAlarm, a personal firewall software, originally created by Zone Labs and currently developed by CheckPoint Software Technologies LTD.

One of ZoneAlarm features is MailSafe, which detects e-mail attachments and warns the user about their presence. When a potentially dangerous attachment is detected, the program quarantines the file with simple renaming of its original file extension, so it breaks the common program association function in Windows and prevents such files from being executed (or launched via associated program).

A file with zm3 file extension originally had NCH file extension (Outlook e-mail tree file). Simple renaming will restore the Windows associations with such file, however it is not advised, unless you are absolutely sure it safe to do.

A zm3 file extension is related to the ZoneAlarm MailSafe component used to protect e-mail. A zm3 file stores renamed Outlook e-mail tree file (nch extension by default).

How to open:

You can rename the ZM3 file extension back to NCH and work with the file normally. This can however be potentially dangerous, because the file was quarantined for a reason. So always re-check it with your anti-virus or anti-spyware programs before you rename the files.

How to convert:

It is unlikely that this file type can be converted to anything else.