Office 365 mscz qurantine

• Mar 14, 2019 - 14:08

Some of our students have started to use musescore and are finding that when emailing .mscz files as attachments in office 365, the emails are not sent and are being quarantined.

I looked into this and it seems office 365 is detecting the attachments as jar files.
I've checked with Microsoft and when I tested changing a random file to .mscz, it sent successfully, so it is not the file extension, it's the content of the file.

has anybody experienced this?



Not that I'm aware of.
mscz is just a normal zip file, so you could have them try and rename their files to .zip (or to whatever you'd like such as .thisisactuallyandmsczfile) and then have the receiving end rename them back again.

In reply to by underquark

Hi both. Thanks for the replies. Office 365 blocks certain attachment types like .jar .reg .exe etc. What I don't understand is why it's viewing a .mscv file as a .jar file.

Microsoft's only suggest was to allow .jar files, which isn't very helpful because they are blocked by default, by Microsoft for a reason.

In reply to by Paul Hesketh

Microsoft block compressed files and archives (since often viruses hide in archives to escape proper scanning).
Since MuseScore's files unfortunately don't have any kind of file magic they can't be detected as such and will look like "normal" zip arcives. The only way to get those files through MS would be to allow zip files ...
definitely not something I would recomend.

In reply to by Lee Batchelor

Please don't confuse everything.
MuseScore files are zipped files.
The product you use prevents usage of zipped files to protect unattentive users against virus.
It is a setting that you can change if you are ready to accept zipped files.
Really NOTHING to do with a MS-Office vs Libre Office war here.

Possible alternatives. Send them using a (free) online service such as dropbox/drive/wetransfer.
If less than 5 scores should be sent/shared, have them upload (privately) to, which is covered by their free account.

I have no problem emailing .mscz files with Microsoft Office, (Outlook 2013 on Windows and Office 365 version on Android), so I'm not sure we've got to the bottom of this. Maybe it's your ISP rather than Microsoft.

Are any of your students able to send them? If so, what's their setup?

Have you tried the Windows 10 mail client?

You could test with Libre Office or OpenOffice: if the problem persists then it points to your ISP or email provider, or maybe even your antivirus.

In reply to by yonah_ag

The problem here is not the mail client (Outlook/Windowss Mail etc.) but the Office 365 Mail server - something like my cloud version of MS Exchange. This service can be configured to block or quarantaine incomming mail with executable/zipped attachments which is what seems to happen to OP.
This is something that can be changed with appropriate configuration but, frankly, blocking such potential hazzardous content from floating in is actually a good idea (our local mail system would allow such content, but only from trusted domains (so teachers can mail them to students etc.)). For even moderatly sized schools it's a good idea to use a LMS like Moodle or ILIAS to host content.

In reply to by rmattes

My Outlook email address has no problem sending/receiving .mscz files and presumably they're also going through Microsoft's mail server – but without being flagged as hazardous, so this still seems a bit odd.

The OP could register an email address with Yahoo or Google and thereby avoid Microsoft's servers and see if the .mscz files then send.

In reply to by yonah_ag

Thanks for all the replies. I tried sending from a gmail account and the email doesn't get through.

In 365 admin, I can see that the email is being quarantined -
'Delete message. Malware: jar File: Theme_and_Variations.mscz'

I think perhaps wetransfer or dropbox may be the way to go, as I don't want to allow zip files through. It's a pain that microsoft doesn't have the option to add custom file extensions as exceptions.

Thanks again for all the responses, very impressed by this forum.


In reply to by frfancha

Hi, I checked in 365 and I was wrong... we do not block zip files. We DO block .jar files and 365 is detecting compressed MuseScore files (.mscz) as a .jar file. However, when we email uncompressed MuseScore files (.mscx), they send with no problem, so this is the solution for now.

Other possible workaround; if they don't need to include pictures into their documents. Have them save as mscx, which is a plain text format and thus shouldn't be hindered by e-mail attachment filtering.

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