.ZLM File Extension

The zlm 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 zlm file extension originally had mst file extension (most likely Windows installer transform script 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.

How to open:

You can rename the ZLM file extension back to MST 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:

As far as we know, this .zlm file type can't be converted to any other file format. This is usually the case of system, configuration, temporary, or data files containing data exclusive to only one software and used for its own purposes. Also some proprietary or closed file formats cannot be converted to more common file types in order to protect the intellectual property of the developer, which is for example the case of some DRM-protected multimedia files.