A Compressed (zipped) Xojo Application Mystery

Anyone care to weigh in on a little mystery?

I’m working on a 32-bit Xojo Mac Cocoa-based desktop app on El Capitan using Xojo 2015r3. I built the app, I code signed the app, I right-clicked the completed app in the Finder and compressed (zipped) the app, and sent it to a friend for a quickie beta test. It bounced back as un-deliverable…because the file was too big…

Action: failed
Status: 5.1.1
Diagnostic-Code: smtp; 554 5.7.0 Message Size Violation

My app is about 15meg normally, and when I compressed (zipped) it, it was about 6meg. Hardly too big.

Here’s the really odd part…

I could send the zipped file (“myprogram.app.zip”) to myself without a problem, but not my friend. (He has a “mac.com” email address. I have my own domain handled email.) He sent me a zipped JPG as big as my zipped app, and I received it no problem. And, I sent it back to him, no problem. I could send him another file, no problem, bigger or smaller, they all worked. In fact, thinking the problem MIGHT have something to with sending apps (executables) and MAYBE Apple (mac.com) is looking at things in some suspicious way,I went into my Applications folder and found another similar sized app, zipped it, and sent it to my friend again, and still no problem. But, if I send MY zipped xojo-built application, it returns with that error of Message Size Violation!

Any of this ring a bell for anyone? Thoughts appreciated!

it’s likely that mac.com unzips the file to check it for viruses. In that case, if the uncompressed file is above their limit, you would also get this error.

Yikes! That’s a very reasonable thought…that they inspect the innards of zipped files, but I’m pretty darn sure my just built app doesn’t include a virus, nor is it really very large! But, I’m open to all thoughts and will check this out…thanks!

Encrypt your files with a password, then you can put that onto DropBox, and send password and link to your friend.

Thanks Michel. I ultimately did get my file to my friend (not using email) so that’s not the real problem. The real problem is only that I’d like to know what’s behind this problem, and if I can trust the zip file I made of my app.

Not sure why you think this is a mystery.

Action: failed
Status: 5.1.1
Diagnostic-Code: smtp; 554 5.7.0 Message Size Violation

That third line tells you that the file is too big as far as that ISP is concerned. I agree that even at its unzipped size it is not that big compared to so many things these days; but, for some reason, those folks have set a rather severe size limitation.

Thanks Harrie. We did send each other a larger file (10 meg rather than the 6 meg we had trouble with) and that worked fine. So, to me, anyway, it’s still a mystery. I can understand why Apple might inspect a file for dangerous content (such as viruses maybe as a service to its customers) but can’t believe they would care about an un-zipped size even if it was 100 meg as long as the zipped file which is sent is 6 meg (or whatever.) But, I just don’t know yet…thanks for the thought.

Gmail will not send a zipped zip file — they open your attachments for viruses as well. Maybe this is what Apple is doing too.

Thanks David, all thoughts welcome! This was a zipped Xojo-created app, not a zipped zip file. And, yes, I can very much believe that Apple might inspect a ZIP file for a virus as you suggested. With that in mind, I copied my zipped app file and the app itself to my PC, and had my Avast Antivirus check them both for viruses, and as I expected, none were found. I think, but don’t know, that the problem is elsewhere.

BUT…I do have a new hint, maybe, which might ring a bell for someone…

I was cleaning up, re-building and decided to throw out the zipped app file that was causing me so much grief, and I couldn’t trash it. The Mac said it couldn’t delete the zip because it was still in use. Not sure why. Another mystery, maybe related or maybe not.

Anyway, thanks David.

Avast PC will not find anything in a Mac executable.

I was hoping it would find a PC virus if one was tagging along somehow in a mac app?? Anyway, just another check…

Typically, a PC virus can attach itself only to Windows or Dos (!) .exe files. There are none in a Mac bundle.

If for any reason the Unix executable inside the bundle is modified, Mac OS X tells you it cannot be opened.

Such security makes viruses in Mac very rare.

I agree that security on the Mac is pretty tight, I haven’t seen anything malicious since 1998, until two weeks ago. My brother-in-law was staying with us and I noticed that his Mac was not only very slow, but everytime a link was clicked a new ‘Ad’ tab would open in his browser.

He gets all his apps from the Mac App Store and knows not to download apps from anywhere else, even ones that claim he has a virus on his computer. His employer’s internal website will only work with Firefox, so I think he must have gone to a site in Firefox that had automatically downloaded and installed an ‘internet plugin’, because in /Library/Internet plugins/ was one claiming to be Panasonic DRM.

I also used ps -ax in the terminal and found a hidden app in a folder called “.fus” which I then killed and removed.

Once these things were removed, he claimed the speed of his computer was like a brand new machine.

This is the first time in 17 years I’ve seen an infected Mac (I used to be an Apple repair guy before programming became my full time job).