Hi Chiron ,
Why just recently? That is very well known old crappy problem
It was discussed & investigated by me loooong(!) time ago

Since I stopped using ZIP with Google, I'm not aware that the issue was not fixed yet … ha! - the bugger is still there Wow!
Read the following - it's an old quote from my post in a different forum
...You can use
winRAR (see note below)
Here is the secret about Gmail and passworded ZIP (
stressing – ZIP)
As you noticed when you open the passworded ZIP the GUI of your archiver will show the content
You can see the list of files inside.
Only when you try to extract particular file (or all of the content) you will be asked about password
What Gmail dumb asses are doing - is checking
just file names!!! at that point , which is "not very clever", softly speaking
It does not check the format of the files as others (clients) do.
So it is enough for them to find EXE extension just because
the list of file names is available.
Try this trick:
- rename <myfile>
.exe to <myfile>
.TXT;
- use the same zipping Utility with password;
- send the archive to yourself;
You will be pleased. That will be sent and received
Google promised to fix that long ago! … note about RAR:Described above will not happen with RAR compressed archives in conjunction with Gmail even if you are not encrypting internal content.
Here we go! use the latter
Sure you can always use 7z (the best! archiver) … there could be some specifics, but please ask after testing if any issues
Hope that helps
Cheers!