Hello, Apple Community - (Users & Groups).

It's from the Norton Security.

It's stand for A-nti V-irus DEF-initionS.

avdefs groups is :

basically, like when you hire a personal security guard and then they wonder around your house and you see them all the time in the back yard or in the kitchen.

You might want to consider uninstalling Norton's; it generally does not play nice with Mac OS and never did; do a search here on the forums which will result in some interesting threads. Also check this:

http://www.thesafemac.com/mac-anti-virus-testing-2014/#more-1308

Norton Antivirus (made by Symantec) has a very long and illustrious reputation for mangling Mac OS X systems, sometimes to the point where a complete reinstall is necessary. Among other things, it installs kernel extensions which are known to cause kernel panics and system freezes; it contains known and documented bugs which can silently corrupt Adobe Photoshop and Adobe InDesign files, destroy a user's ability to authenticate as an administrator, and (on PPC systems) can cause Classic to stop functioning; and Symantec has on at least two occasions now released flawed .dat file updates which erroneously report certain critical Mac OS X files as "viruses." (Deleting these "viruses" causes damage to the system that in some cases renders it unbootable.)

Norton has also been reported as damaging iPhone backups.

Norton Removal Tool (Symantec Uninstaller):

http://www.symantec.com/business/support/index?page=content&id=TECH103489&locale =en_US

Hi,

Sorry for the trouble, do you have any other security products installed along side of Norton? also may I know which Norton product are you running?

Thank you!

Praveen

Norton Support.

Hi There, My first suggestion would be to check out the Group but

1) Opening any file

2) Go to "Get Info"

3) go to "Sharing & Permissions" if by some chance the group name is listed or shows up in, you may have an unwanted and uninvited user but make sure it is not the University before you push any panic buttons further more assess more of your files using a random file selection approach.

then i suggest go to the ASL ( Apple Systems Log) and do some more assessing of what is happening, the log may tell you something or it may not.

The power of the ASL is 2 fold 1) you gain information as to what is happening on your device 2) You can send the log to Apple which allows Apple the opportunity to assess various Technical aspects of the device, your personal info does not go with the log

If you have an unwanted user, back up your files and do a full reinstall via Disc Utility do not waste time on this decision if a reinstall is needed.

Good Luck