TheAlarmTech.com

the SDU is just a zip file.
SDU extension is for the SDU program only, windows/7-zip will not know want to do with it.
maybe on one of the pc is associating the SDU extension as a zip file?
is it changing the extension? change it back?

hopefully this is helpful

Not sure where this thread belongs so I am sticking it here. I am one of a few techs who works with EST and we are constantly sharing SDU exports with one another. When we email them to one another however, they are downloading to our computers as zip files (7-zip), not as filename.SDU. Wasn't sure if anyone else has ever come across this or not. When I download to my Mac I see the packaged .SDU file and everything is happy. I didn't see any file associations in 7-zip for SDU files. Any help on this would be great. Thanks.