How to open ZoneAlarm Mailsafe renamed VB file .z1 files
Have you had trouble opening the z1 file on your computer? What are z1 files? We explain what they are and recommend software that we know will open them.
What is z1 file?
Files with z1 extension are used by the ZoneAlarm firewall software. They contain some various data for internal purposes.
ZoneAlarm Mailsafe renamed VB file description
The z1 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 z1 file extension originally had VB file extension (Visual Basic 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.
Suggested software to open z1 file

ZoneAlarm Pro
A popular firewall software
There are other Z1 filename extensions with the same .z1 suffix
z1 - Infocom game module for Z-machine version 1
A z1 file extension is related to the Infocom software. A z1 file stores game module for Z-machine version 1.