I checked what takes disk space and found out that Express keeps all previous installers...
It saves them in this hidden folder:
C:\ProgramData\Garmin\CoreService\Downloads\Application\
And it gets bigger after every update.
So every user must delete those files by hand, from time to time, to not waste disk space.
.
This is a very bad design. I can't imagine why anybody would be that evil to do such nasty thing or maybe someone was just stupid.
.
This could be a feature, but then it must be disabled by default and only user should be able to turn it on.
Checkbox "Keep all older version" with clear information to which directory save them - is a must.
.
Now this is just very wrong.